Genetic

Genetic

• 1. Genetic Genetic
• 2. Genetic Genetic or heredity science is a branch of biology that examines the inheritance and diversity of organisms. Turkish in the German last genetic word in 1831 Greek γενετικός - genetikos ( "genitive") was derived from the word. The origin of this word is based on the word kökenνεσι gen - genesis. With the awareness that the characteristics of living beings are hereditary, plants and animals have been rehabilitated since prehistoric times. However, modern genetic science, which seeks to understand hereditary transmission mechanisms, began only in the mid-19th century with the work of Gregor Mendel . Mendel did not know the physical basis of heredity, he observed that these traits were transferred in a discrete manner; Nowadays these inheritance units are called " genes ". Genetic
• 3. Genetic Genetic Genes correspond to certain regions in DNA. DNA is a chain molecule consisting of four types of nucleotides. The sequence of nucleotides on this chain is genetic information (information) inherited by organisms. In nature, DNA has a two-chain structure. The nucleotides in each "strand" in the DNA complement each other, that is, each strand has the property of being a mold to form a new strand of its own. This is the physical mechanism for the reproduction and inheritance of genetic information.
• 4. Genetic Genetic The sequence of nucleotides in DNA is used by the cell to produce amino acid chains. Of these, the protein is formed. The order of amino acids in a protein corresponds to the sequence of nucleotides in the gene. This relationship is called the genetic code. The sequencing of amino acids in a protein determines how the protein will form a three-dimensional shape. The shape of this structure is also responsible for the function of the protein. The proteins perform almost all functions necessary for the survival and reproduction of cells.
• 5. Genetic Genetic A change in the DNA sequence alters the amino acid sequence of a protein and hence its shape and function: this can lead to significant consequences in the cell and its associated living. Although genetics plays an important role in determining the appearance and behavior of organisms, the interaction of the organism with the environment and the genetic interactions take place in the formation of the result. For example, while genes play a role in the length of a person's length, one's childhood nutrition and health also has a great impact.
• 6. History History Although genetic science began with the practical and theoretical work of Gregor Mendel in the mid- 1800s, other theories about heredity existed before Mendel. A popular time of Mendel's theory, blending inheritance was the concept: the individual, the characteristics of the parent uniform was the idea that a mixture inherit it. Mendel's studies have misrepresented this, showing that features are a combination of discrete genes, not a blend of traits. (For example, when red and white-eyed flies mate, their offspring will be either red or white-eyed, but not pink-eyed.)
• 7. History History People's experiences do not change the genes they transfer to their offspring. Other theories included the idea of Charles Darwin 's Pangenezis (suggesting both hereditary and acquired characteristics) and Francis Galton 's new commentary on Pangenezis that the inheritance was both granular and hereditary. Another theory that is valid at that time is the inheritance of acquired propertiesHe was convinced that people had characteristics that were strengthened by their parents. It is known that this idea (generally attributed to Jean-Baptiste Lamarck) is wrong today.
• 8. History History Another theory that is valid at that time is the inheritance of acquired propertiesHe was convinced that people had characteristics that were strengthened by their parents. It is known that this idea (generally attributed to Jean-Baptiste Lamarck) is wrong today. People's experiences do not change the genes they transfer to their offspring. Other theories included the idea of Charles Darwin 's Pangenezis (suggesting both hereditary and acquired characteristics) and Francis Galton 's new commentary on Pangenezis that the inheritance was both granular and hereditary.
• 9. The first genetic experiment, Mendel and Classical Genetics The first genetic experiment, Mendel and Classical Genetics The root of modern genetics is based on the observations of Gregor Johann Mendel, an Austrian (German-Czech) Augustine monk and a botanist. Mendel, who is considered to be the father of this popular science of our time, has done detailed studies on the heredity characteristics of plants. Since 1856 Mendel began to collect seeds from various varieties of pea ( Pisum sativum ) and to examine them in the monastery garden. After 10 years of observation and experimentation, he published the most important findings of this work in his famous e Versuche Über Pflanzenhybriden mel ( br Trials on plant hybrids Pf ) and presented it to the Brunn Natural History Association in 1865.
• 10. The first genetic experiment, Mendel and Classical Genetics The first genetic experiment, Mendel and Classical Genetics Mendel followed the hereditary repetition of some features in pea plants and demonstrated that they could be identified mathematically. Mendel's work has suggested that heredity is not acquired, it is granular, and that the inheritance of many traits can be explained by simple rules and proportions. At that time, DNA , chromosomes , meiosis of concepts such division is not yet disclosed, and Given is not known, Mendel's just phenotypic (observable) of the assessment is made according to the character of separation be said to be extremely successful.
• 11. The first genetic experiment, Mendel and Classical Genetics The first genetic experiment, Mendel and Classical Genetics Until the 1890s after Mendel's death, the importance of his work was not widely understood. At that time, other scientists working on similar problems rediscovered his work. Three biologists in the Netherlands called Hugo De Vries, Correns in the Netherlands, and E. Von Tschermak in Germany showed the validity of the Mendelian laws in their research on different plant species, unaware of each other and collected all the results under the name "Mendel's laws".. Mendel's study also suggested the use of statistical methods in heredity studies .
• 12. The first genetic experiment, Mendel and Classical Genetics The first genetic experiment, Mendel and Classical Genetics After the rediscovery and popularization of Mendel's work, many experiments have been done to unearth the molecular basis of DNA. Based on his observations on the white-eyed Drosophila (fruit fly), Thomas Hunt Morgan suggested that genes were involved in chromosomes in 1910 and revealed the presence of mutations in 1911. Morgan's student Alfred Sturtevant used the phenomenon of genetic linkage and in 1913 published the first enc genetic map showing the sequencing and ordering of genes along the chromosome.
• 13. The first genetic experiment, Mendel and Classical Genetics The first genetic experiment, Mendel and Classical Genetics The term "genetics" was proposed in a letter to Adam Sedgwick in 1905 by William Bateson, a prominent advocate of Mendel's work. In his inaugural speech, held in London in 1906, Bateson used the term Uluslararası genetic yapılan to describe the study of heredity, which made the term more widespread. ( genetics as an adjective , derived from genesis - sıfνεσι; ("source"), and from genno - daεννüre ("breed"), in terms of biological meaning, 1860 times was used) )
• 14. Molecular genetics Molecular genetics Previously, it was known that chromosomes contained genes and were composed of protein and DNA , but it was not known which heredity was responsible. In 1928, Frederick Griffith explained the phenomenon of transformation he discovered in his published article. 16 years later, in 1944, Oswald Theodore Avery, Colin McLeod and Maclyn McCarty demonstrated that the molecule responsible for this transformation was DNA. Hershey-Chase experiment in 1952 proved that DNA (as opposed to protein) was the genetic material of viruses , and that the other molecule could not be responsible for heredity.
• 15. Molecular genetics Molecular genetics In 1953, James D. Watson and Francis Crick solved the structure of DNA and demonstrated that the DNA molecule had a helical structure using the results of Rosalind Franklin 's X-ray diffraction study. Their double helix model showed that the nucleotide sequence was complementary spouse in the other strand. This structure not only showed the sequencing of nucleotides, but also demonstrated its physical mechanism for replication: when two strands were separated from each other, each strand could use its own sequence as a template for the formation of a new strand.
• 16. Molecular genetics Molecular genetics This structure explains the process of heredity; How DNA affects cell behavior is not yet known. In later years, some scientists have sought to understand the mechanism by which DNA controls the protein production processes in ribosomesand found that the genetic code of DNA is read and resolved by messenger RNA (mRNA). RNA is a DNA- like molecule composed of nucleotides; The nucleotide sequence of mRNA is used to generate the amino acid sequence in proteins. The translation of the nucleotide sequence into the amino acid sequence takes place via the genetic code.
• 17. Molecular genetics Molecular genetics The inventions at this molecular level on heredity provided an understanding of the molecular structure of DNA and the explosion of research into new knowledge in biology. In 1977, Frederick Sanger's chain-terminated DNA sequencing method was an important development; this technology allowed scientists to read DNA molecules. polymerase chain reaction developed by Kary Mullis in 1983 enabled DNA isolation and the replication of the desired regions of DNA fragments easily. These and other techniques and the teamwork of the Human Genome Project on the one hand and Celera Genomics on the otherIn 2003, human genome sequences were fully exposed to light.
• 18. Discrete inheritance and Mendel's laws Discrete inheritance and Mendel's laws At the most basic level, inheritance in organisms occurs through the discrete features we call genes today. (size of a feature two, or this feature has been gathered around a few values are discrete, if it shows a constant value distribution is continuous ), this first contact on the observation of the subject, the pea plants were also inherited traits worked on the decomposition Mendel Gregor respectively. his research on flower color, Mendel observed that each flower was either purple or white, not an intermediate color. Different, discrete versions of the same gene are called alleles .
• 19. Discrete inheritance and Mendel's laws Discrete inheritance and Mendel's laws Mendel sown in the garden collecting seeds from each of the different plant varieties. Mendel, who subjected pea plants to regular aktarıl pollination eler, discovered that 7 properties did not change in these and observed how these 7 features (shape, color, length of plants etc.) of peas were transferred from fertile to pea. Each offspring differentiated the individuals he obtained from each other and his parents according to whether they were similar or not. Thus, 7 different species have obtained different characteristics. He found that in certain cases he did not change certain characteristics. He called each of these features ”pure trait Bu. When the two spouses "pure property" were crossed, only this pure property emerged, which is the basis of the Mendelian law.
• 20. Discrete inheritance and Mendel's laws Discrete inheritance and Mendel's laws Mendel also observed that some features dominated the crosses he made. For example, as the length character dominated the brevity character, the hybrid individuals were long in appearance. As a result of crossing two long hybrids, it was 25% pure long, 25% pure short, 50% hybrid long. In the trial of the color of the flowers of the pea plant, Mendel observed that the color was either purple or white, and that the color of these two colors did not form a color. These different versions of the same gene are called alleles.
• 21. Discrete inheritance and Mendel's laws Discrete inheritance and Mendel's laws In pea plants, each organism has two alleles of each gene. In many organisms , including human beings, this model of inheritance is valid. (The gene in genetics such as microorganisms, one of the parents of the two alleles is assumed to pass from the father of the other.) Homozygous organisms which comprises two copies of the same allele, while the organism has two different alleles are heterozygous called.
• 22. Discrete inheritance and Mendel's laws Discrete inheritance and Mendel's laws Genetic structure of alleles in an organism is called genotype. The observable properties of the organism are called the phenotype. In heterozygous organisms, the characteristics of the alleles generally determine the phenotype of the organism to suppress that of the other; The qualifications of alleles are called gözlem dominant eki (dominant), which dominate the phenotype of the organism, and the other allele whose attributes are observed not to dominate the phenotype is called olan recessive al. However, it is sometimes seen that an allele is not literally dominant, which is called tam incomplete dominance Bun. Sometimes it is observed that the qualities of both alleles are effective, and this is called ir coditude.
• 23. Symbolic representation system and diagrams Symbolic representation system and diagrams Genetics use diagrams and symbols to describe heredity. A gene is represented by one or several letters. In this representation, the upper case dominates the allele, the lower case represents the recessive allele. Usually a al + ant symbol is used to represent a normal, non- mutant allele for a gene. Fertilization and in Mendel's about breeding experiments parent, " parent " the initials of the words "P", the offspring (pups) and F1 (the "F" " filial " initials of the word, "1" within the meaning of the first generation) is referred to. When the offspring of the F1 generation mate with each other, the new generation of the offspring is referred to as F2. One of the common schemata used to predict the result of the crossing is known as the "Punnett frame".
• 24. Interaction of genes Interaction of genes Organisms contain thousands of genes, and the co-occurrence of these genes in organisms reproducing by sexual mating is generally independent of each other. That is, for example, the inheritance of a yellow or green pea allele is unrelated to the inheritance of alleles that determine whether the flowers are white or purple. " The second law of Mendel, " or "independent assortment Act, known as" In these cases, the parents both get shuffled the alleles of different genes, with many different combinations when creating offspring means to get together. (However, some genes that show "genetic linking" will not come together independently, as will be discussed in more detail below.)
• 25. Interaction of genes Interaction of genes As is often the case, different genes can interact with each other in a way that allows them to have the same property (phenotype). The genes of the Omphalodes verna plant of European origin are examples of this. In this plant, there is a gene with two alleles that make the color of the flowers blue or magenta . However, there is another gene in this plant that controls whether the flowers will be colored, that is, colored or white. When the plant has two copies of the white allele of this second gene, the flowers become white without causing one of the blue and magenta alleles in the first gene to be effective in the plant. This interaction between genes is called epis epistasis.
• 26. Interaction of genes Interaction of genes Many features are continuous properties (such as human size and skin color) rather than discrete property (such as white or purple flowers). These complex features are the product of many genes. The effects of these genes are equilibrated to varying degrees by the effects of the environment in which the organism is experiencing. The degree to which an organism's genes contribute to such a complex feature is called özel inheritance Bir. The inheritance measure of a property is relative, depending on the changing effects of the environment on that property. For example, while the heritability of the mixed characteristic we call the height of the human is determined to be 89% in the US, this rate is only 62%, since the environment has a greater impact in a poor country such as Nigeria where there are nutritional and health problems.
• 27. Molecular basis of inheritance Molecular basis of inheritance DNA and chromosomes: The molecular basis of genes is deoxyribonucleic acid (DNA). DNA also consists of a chain of 4 types of nucleotides: adenine (A), cytosine (C), guanine (G), and thymine (T). Genetic information (inheritance information) exists in the sequence of nucleotides, and the genes are present as arrays along the DNA chain. The only exception to this rule is viruses ; viruses sometimes use the RNA molecule that is similar to DNA ; because the genetic material of viruses is RNA.
• 28. DNA and chromosomes DNA and chromosomes DNA is normally a two-stranded molecule that circulates in a binary helix. Each nucleotide in one of the two strands of DNA forms a pair with the nucleotide partner in the opposite thread; that is, A creates a pair with T, C with G. Thus, each of the two strands has all the necessary information, and in the other strand there is a backup of this information. This structure of DNA is the physical basis of heredity. In DNA replication , the genetic information is copied by the separation of the strands and the use of each strand as a template of the new strand.
• 29. DNA and chromosomes DNA and chromosomes Genes are arranged in a linear order along the DNA sequence chains called chromosomes . Although each cell in bacteria has a simple circular chromosome, eukaryotic organisms, including plants and animals, have DNAs arranged in multiple linear chromosomes. These DNA chains are extremely long; for example, the longest human chromosome has a length of 247 million base pairs. DNA in a chromosome forms a structure called chromatin , together with structural proteins that regulate, compress and control access . In eukaryotes, chromatin is generally composed of nucleosomes , which are structures that consist of histone proteins, which are located at regular intervals on DNA, wrapped around the DNA. The whole of the inherited material in an organism (ie, in general, all of the DNA sequences in all chromosomes) is called the genome.
• 30. DNA and chromosomes DNA and chromosomes Although haploid organisms have only one copy of each chromosome, most of the animals and diploids, including many plants, contain two copies of each chromosome and therefore two copies of each gene. Two alleles of a gene are located in the same de loci al (s) in their sister chromosomes; each of these alleles was taken from one parent (one mother and one father).
• 31. DNA and chromosomes DNA and chromosomes An exception to this is the sex-determining sex chromosomes involved in determining the sex of the organism. Although the Y chromosome with very few genes in these chromosomes (eg, chromosome pairs in humans) has very few genes in humans and mammals, the other X chromosome resembles the other chromosomes and contains several genes not related to sexual identification. Females have two copies of X chromosomes, while men have an X and a Y chromosome. Thus, examples of unusual inheritance, which arise as sex-related diseases, are also due to this numerical difference in the copy of the X chromosome.
• 32. Reproductive Reproductive When the cells are divided, their entire genome is copied, and each cell cell inherits a copy of it (inherits). This process, called mitosis , is the simplest form of reproduction and is the basis of olup asexual reproduction Mit. Asexual reproduction can occur in some multicellular organisms, in a way that allows for the breeding of a foster (progeny) that inherits the genome of one of the parents. Genetically, the offspring of the parent are called clones. In eukaryotic organisms, there is usually sexual reproduction Ö. In sexual reproduction, a progeny is produced which contains a mixture of hereditary material from both parents.
• 33. Reproductive Reproductive In the process of sexual reproduction, haploidand diploid cell types are an alternate sort. Haploid cells fuse together to combine genetic material and create a diploid cell with double chromosomes. Diploid organisms, DNA replicationthey form haploid cells. The haploid cells that occur in this way receive one or the other of each chromosome pair randomly. Most animals and plants spend almost all of their lives as diploids, and haploid forms consist of unicellular gametes only.
• 34. Chromosomal fragment exchange and genetic linkage Chromosomal fragment exchange and genetic linkage The diploid nature of the chromosomes provides the genes in different chromosomes with "independent decomposition" during sexual reproduction, creating new gene combinations. The genes in the same chromosome would never, if they were not in the process of recombination of the genes to form new gene combinations, if there was no process called crossover where the chromosomes changed parts . During this process, chromosomes exchange DNA fragments to alter gene alleles. This chromosomal fragment exchange process is usually during meiosis, ie gametin haploid " germ cellsIt occurs during a series of cell divisions that make up.
• 35. Chromosomal fragment exchange and genetic linkage Chromosomal fragment exchange and genetic linkage The possibility of recombination that may occur between two specific points in the chromosome depends on the distance between these two points. Since there will always be recombination between genes far enough away, alleles of these genes are randomly distributed. In the case of relatively close genes, the low probability of crossover means the genetic linkage of these genes; the alleles of both genes tend to be co-inherited. The amount of linkage between the sequences of genes creates a linear link map, which roughly corresponds to the arrangement of genes throughout the chromosome.
• 36. Gene expression Gene expression Genetic code: Genes express their functional effects by the production of proteins, usually responsible for most of the functions in the cell. Proteins are amino acid chains and DNA sequence of a gene (an RNA -through) is used to produce a specific protein sequence. This process, called a transcription, begins with the production of an RNA molecule that has a sequence that leads to the DNA sequence of the gene. Then, this messenger RNA molecule translationis used to produce an amino acid sequence corresponding to the information in the RNA sequence.
• 37. Genetic code Genetic code Each of the three nucleotides in the RNA sequence is called a codon, each of which corresponds to one of the 20 amino acids that make up the proteins. This relationship between the RNA sequence and the amino acids is called the genetic code. This information flow is unidirectional; the information is transferred from the nucleotide sequence to the amino acid sequence of proteins, not from the protein to the DNA sequence. This phenomenon was called "central dogma of molecular biology" by Francis Crick .
• 38. Genetic code Genetic code A protein amino acid sequence forms the three-dimensional structure of that protein, which is closely related to the function of the protein. Some of these are collagen, such as formed by the protein fibers are simple structural molecules. Enzyme called protein may be linked to other proteins and simple molecules, facilitating chemical reactions within the bound molecules (without changing the structure of the protein) the catalyst play a role. The structure of the protein is dynamic; The hemoglobin protein, for example, facilitates the uptake, transport and release of oxygen molecules in the mammalian blood, while bending and twisting takes different forms.
• 39. Genetic code Genetic code Even the difference of a single nucleotide in DNA can cause a change in the amino acid sequence of a protein. Since the structures of proteins are the result of their amino acid sequences, such a change can alter the properties of that protein; for example, it may alter the properties of the protein in such a way that it deteriorates stability in the structure of the protein or changes in the interaction of that protein with other proteins and molecules. Sickle disease, called sickle cell anemia, is an example of this. This disease results from a single base difference in the coding region that determines the β- globin portion of hemoglobin; this differentiation of a base causes an amino acid change which causes the physical properties of hemoglobin to change.
• 40. Genetic code Genetic code Sickle cell hücre versions of hemoglobin, which arise as a result of the change of their physical properties, adhere to each other, stack on top of each other and form fibers. These fibers lead to degradation of the red blood cells which transport the protein. Sickle- shaped cells cannot flow comfortably within the blood vessels and tend to clot or obstruct the vessel. These problems eventually lead to medical problems related to the disease.
• 41. Genetic code Genetic code Some genes are replicated in RNA but are not translated into proteins, which are called prote non-coding RNA molecules. These products, in some cases, play a role in structures related to critical cell functions ( such as ribosomal RNA , carrier RNA). RNA may also have a regulatory effect role through "hybridization" interactions with other RNA molecules. (Eg microRNA)
• 42. Congenital - acquired Congenital - acquired Genes contain all information about the functioning of an organism, but the environment plays an important role in determining the final phenotype. The genetic factor and the environmental factor dilemma, which are used in the sense of İngilizce those acquired with the innate sonradan, the English şt nature versus nurture, (in short, nature vs. nurtureis expressed in the words of nature and growing dichotomy. The phenotype of an organism depends on the interaction of the environment and the environment. The case of heat sensitive mutations “is an example of this. Generally, an amino acid that changes within a protein sequence does not alter its behavior and its interaction with other molecules; but it destabilizes the structure.
• 43. Congenital - acquired Congenital - acquired Since molecules at higher temperatures move faster and collide with each other, such an amino acid change leads to disturbances in the protein, which are characterized by degradation ( denaturation ) and poor functioning. In low temperature environments, the structure of the protein remains stable and its functioning continues in its normal state. This kind of mutation Siamese cat The color mutation in an enzyme responsible for pigment production leads to deterioration of its structural stability and weakness in the skin, while the protein in the colder areas such as the leg, the ear, the tail, without weakening its functioning; thus, the cat has a dark fur.
• 44. Gene regulation Gene regulation Although the genome of an organism contains thousands of genes, not all of these genes need to be active at a particular time. A gene is " expressed " when mRNA transcription occurs (and turned into protein) . There are many cell methods that control the expression of genes. For example, proteins are produced only when cells are needed. Transcription factors are proteins that regulate the transcription of the gene by either promoting or inhibiting. For example, the amino acid of tryptophan in the genome of the bacterium Escherichia coli There is a series of genes required for synthesis; but after tryptophan is ready for use in the cell, these genes are no longer needed. The presence of tryptophan directly affects the activity of genes; Tryptophan molecules bind to the repres tryptophan repressor ın (a transcription factor). The tryptophan repressor of gene transcription stops and expression, and hence, the tryptophan synthesis process " negative feedback " (negative feedback) would have secured the embodiment.
• 45. Gene regulation Gene regulation Differences in gene expression are particularly evident in multicellular organisms, although in such organisms all of the cells contain the same genome, they have very different structures and behaviors that result from the expression of different gene clusters . All cells in a multicellular organism are derived from a single cell. During the process in which this single cell differentiates into different cell types, it reacts to external and intracellular signals , forming different types of behavior by gradually establishing different gene expression patterns.
• 46. Gene regulation Gene regulation A single gene is not responsible for the development of structures in multicellular organisms; these different types of behavior arise from complex interactions between many cells. Structural properties of chromatin in eukaryotes affect the transcription of genes. Such as ' epigenetic ' tr (upper-hereditary), since the effects are located above the DNA sequence and retain transduced from one cell line. Epigenetic properties, different cell types formed in the same environment can have very different characteristics.
• 47. Genetic change Genetic change Mutations: During the DNA replication process, random inaccuracies occur in the polymerization of the second strand . These errors, called mutations or changes, can have a strong effect on the phenotype of the organism, especially if they occur in the protein coding sequence of a gene. However , due to the ability of the DNA polymerase enzyme to correct errors, the rate of these errors is extremely low; The error rate was observed as 1 error per 10-100 million basis. Processes that increase the rate of change in DNA are said to be mutagenic . Mutagenic chemicals usually match the baseby interfering, they lead to errors in DNA replication. Ultraviolet radiation causes mutations by damaging the DNA structure. chemical damage to DNA occurs naturally, cells use gelmek DNA repair yolla mechanisms to repair mismatches and disturbances. However, repair may sometimes not return DNA to its original state.
• 48. Mutations Mutations Erosion during meiosis (similarity of similar sequences in two chromosomes) may also cause mutations in organisms that exchange chromosomal fragments with crosover and reincarnate genes. These errors are particularly likely due to the misalignment of partner chromosomes, which are caused by similar sequences; this makes some regions of the genomes more prone to mutation. These errors create large structural changes in the DNA sequence; accidental transfer of parts between chromosomes , duplications (duplications), inversion (deletions), deletions in large areas of chromosome (translocation). Human DNA has approximately 25,000 genes, and more than 6,000 genetic diseases have been identified and treated. Mutations, especially cancer, mental retardation, premature aging and thousands of other diseases are known to lead.
• 49. Natural selection and evolution Natural selection and evolution Mutations cause the emergence of different genotypes and these differences result in different phenotypes. Many mutations organism's phenotype, health and (related to natural selection) reproductive adaptation (Eng. Fitness ) has little effect on. Mutations that have an effect are usually harmful, but sometimes there are mutations that can be called beneficial in the context of the environment in which the organism is involved. Population genetics is a genetic subclass that investigates the sources and distributions of these genetic differences in populations and how these distributions change over time.
• 50. Natural selection and evolution Natural selection and evolution The frequency of an allele in a population can be affected by natural selection ; The high rate of survival and reproduction of individuals with a specific allele may cause that allele to become more frequent in that population over time. At the same time, there may be changes in the allele frequency, called the " genetic drift, " by the effect of the luck factor, that is, the random flow of events. The genetic drift is defined in the gene pool of a population, as distinct from the natural selection, but not from the selection of appropriate genes, but from the generation to generation, which is considered to be entirely accidental.
• 51. Natural selection and evolution Natural selection and evolution The genomes of organisms can vary over many generations, resulting in a phenomenon called evolution . As a result of the selection for mutations and the beneficial ones of the mutations, it can lead to the evolution of a living species into more harmonious forms. This process is called adaptation. New species are formed by the process called speciation. Speciation usually arises from the genetic differentiation caused by geographically distinct populations of different populations. Since the DNA sequences move away from each other during evolution , these differences between sequences can be used as a "molecular clock" in calculating the evolutionary distance between them.
• 52. Natural selection and evolution Natural selection and evolution Genetic comparisons are generally qualify the evolutionary relationship between species is considered to be the most accurate method, this method is phenotypic acquired with some misleading comparative evaluations are also corrected. The evolutionary distances between species are represented by diagrams called the inden evolution tree birbir or ini phylogenetic tree, which illustrate the descent of species from a common ancestor and the distancing of species from time to time. However, the horizontal gene transfer between these tree schemes species cannot show events.
• 53. Research and technology Research and technology Model organisms Although geneticists initially studied a broad spectrum of genetically broad organisms, researchers later began to specialize in a subset of organisms. A significant amount of research into a particular organism has encouraged new researchers to further refine the same organism. Thus, several model organisms have been the basis for a significant part of the current genetic research. main research topics in genetics of model organisms are gene regulation, morphogenesis, developmental genes and cancer.
• 54. Model organisms Model organisms Model organisms have been selected in part because of their practical use; short production times, easy genetic manipulation have caused some organisms to become popular in genetic research. Widely used model organisms include the gut bacterium Escherichia coli , crucifers from the genus Arabidopsis thaliana plant, a yeast species of Saccharomyces cerevisiae , the nematode Caenorhabditis elegans , the common fruit fly, Drosophila melanogasterand house mouse Mus musculus thereof.
• 55. Different research areas Different research areas In addition to advances in genetic science, the fact that research has begun to specialize in different fields has led to the formation of sub-branches of this branch of science. Some of the sub-lines of genetics include: ●Genetics of evolutionary development ( Génétique évolutive du développement) : The fertilized single cell examines all the molecular factors in the formation of the organism starting from the egg stage and hence the genes that encode them. It is intensely involved in mechanisms that enable the transition from a simple biological system (single-celled, radial symmetry) to a complex organism (multicellular, usually metamerative and specialized organisms). Types of model organisms to study the mechanisms of organism formation ( Drosophila, round worms, zebrafish, chickenetc.). This branch, known as the genetics of evolutionary development in French, is known as the biology of evolutionary development in English. ●Medical Genetics
• 56. Different research areas Different research areas ●Genomics :Examines the structure, composition and evolution of thehuman genome (the three billion base pairs, the entire DNA sequence in the chromosomes) and the units that can have a biological meaning in DNA ( genes , transcription units, non- translationalunits, microRNAs, regulatory units, promoters with transcription factors, CNG tries to define alpha and beta channels, etc.). ●Quantitative genetic : examines the genetic components by explaining the variation (alteration, diversification) and the inheritance of the quantitative characteristics (height, hair color, growth rate, etc.). ●Genetics of evolution : examines the traces of natural selection in genomes of species andtries to identify genes that play a key role in thesurvival and adaptation of species in changing environments (environments).
• 57. Different research areas Different research areas ●Population genetics : Examines the forces (and effects or consequences) affecting the diversity of populations and species by developing mathematical and statistical methods. In other words, it is a genetic subgenus which investigates the sources of similarities and differences of individuals in populations. It conducts research on four main items: natural selection, gene pool, mutations and gene continuity. ●Molecular genetics : It is a genetic sub-genre that examines the structure and functions of genes that are the heredity material of living things at the molecular level. Molecular genetics works by using methods of molecular biology and genetics. ●Ecological genetics : Genetic studiesare a genetic sub-genre that continues in the ecological field. Ecological genetics explores the populations of living things in close relation with "population genetics".
• 58. Medical genetic research Medical genetic research Medical genetics is investigating the relationship between genetic diversity, human health and diseases. When an unknown gene that can cause a disease is searched, researchers often benefit from the, genetic link gen and genetic genealogy chart to determine the position of the genome associated with the disease. In population- level research, researchers use the araştır Mendelian randomization alar method to determine the location of genes related to diseases in the genome ; this technique is particularly useful in a number of gene-related (multi-gene) properties, which cannot be precisely determined by a single gene.
• 59. Medical genetic research Medical genetic research As soon as any gene found to be a disease gene was found to be a candidate, further investigations are usually performed on the gene ( ortholog gene) that is the equivalent of a gene in a model organism . Genotyping techniques, as well as hereditary disease studies, has also led to the development of the pharmacogenetic field which investigates how genotype affects the response to the drug .
• 60. Medical genetic research Medical genetic research Although cancer is not inherited from generation to generation, it is now considered a genetic disease. development of cancer in the body is a combination of various events. Sometimes mutations occur when the cells in the body are divided. Although mutations in these cells are not transferred to a child, they can affect the behavior of cells and sometimes cause them to grow and divide faster. cellsthese are mechanisms that inhibit abnormal and inappropriate divisions; signals for the death of improperly dividing cells. But sometimes other mutations can cause proliferating cells to disobey these signals. There is a kind of internal natural selection process in the body; mutations that continue to divide the cell accumulate in the cells, eventually a cancer tumor occurs. The tumor grows and develops and invades various tissues of the body.
• 61. Research techniques Research techniques Nowadays, DNA can be changed in many ways in the laboratory. The restriction enzymes used in laboratory studies are used to cut DNA in certain sequences to produce the desired fragments. Ligation enzymes provide the possibility of recombining, or combining, these fragments thus obtained, so that researchers can combine bee recombinant DNA by combining DNA fragments from different sources (biological species) . Generally " genetically modified organism " a (the English abbreviation GMO) recombinant DNA is commonly used in the study, the plasmids(Circular DNA fragments with a few genes on them).
• 62. Research techniques Research techniques By introducing plasmids into the bacteria and enlarging the ı agar DNA plates of these bacteria (to isolate clones of bacterial cells), the researchers can clone the inserted DNA fragments cloned, which is a process known as molecular cloning. (The term cloning is also used to create clonal organisms using various techniques.) DNA can also be amplified using a process called polymerase chain reaction (PCR). PCR can isolate and maximize a targeted region of DNA using specific short DNA sequences. PCR is often used to detect the presence of specific DNA sequences, as it can excessively amplify extremely small fragments of DNA.
• 63. DNA sequencing and genomics DNA sequencing and genomics DNA sequencing , one of the most basic technologies developed in genetic studies, allows researchers to determine the nucleotide sequence in DNA fragments . A DNA sequencing method ( chain termination sequencing ) developed by Frederick Sanger and his colleagues in 1977 is now used as a routine method for sequencing DNA fragments. Researchers Thanks to this technology, the molecular sequences associated with many human diseases have been able to study.
• 64. DNA sequencing and genomics DNA sequencing and genomics As DNA sequencing becomes cheaper and with the help of computers, researchers have sequenced the genome of many organisms . To do this, sequenced DNA fragments are aligned with the same sequence of sequences, and sequences of larger regions are determined (the genome construction process). These technologies are also used for human genome sequencing of the human genome project was completed in 2003. New high-volume sequencing technologies rapidly reduce the cost of DNA sequencing, with most researchers expecting the cost of sequencing of a human genome to close to $ 1,000 in the near future.
• 65. DNA sequencing and genomics DNA sequencing and genomics The increasing use of DNA sequencing methods as a result of determinations, the increasing number of useful sequencing has led to the research area of genomics, which uses computational tools and analysis samples in researches in genomics of organisms. Genomics can also be regarded as a subtext of the scientific discipline of bioinformatics.
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