Genetic diversity definition

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Classic concepts of genetic (gene) diversity (heterozygosity) such as Nei & Li’s nucleotide diversity were defined within a population context. Although variations are often measured in population context, the basic carriers of variation are individuals. Hence, measuring variations such as SNP of an individual against a reference genome, which has been ignored previously, is certainly in its own right. Indeed, similar practice has been a tradition in community ecology, where the basic unit of diversity measure is individual community sample. We propose to use Renyi’s-entropy-based Hill numbers to define individual-level genetic diversity and similarity and demonstrate the definitions with the SNP (single nucleotide polymorphism) datasets from the 1000-Genomes Project. Hill numbers, derived from Renyi’s entropy (of which Shannon’s entropy is a special case), have found widely applications including measuring the quantum information entanglement and ecological diversity. The demonstrated individual-level SNP diversity not only complements the existing population-level genetic diversity concepts, but also offers building blocks for comparative genetic analysis at higher levels. The concept of individual covers, but is not limited to, individual chromosome, region of chromosome, gene cluster(s), or whole genome. Similarly, the SNP can be replaced by other structural variants or mutation types such as indels. SNPs (single nucleotide polymorphism) are single-nucleotide substitut...

Various plants and animals inhabit an ecosystem. This variety in the various life forms living in an ecosystem is called biodiversity. Furthermore, biodiversity has different levels, which are - species diversity, genetic diversity, and ecosystem diversity. The genetic make-up of every individual is different. And this is determined by the genes or heredity. Genes evolve over a period depending upon the environmental conditions and help individuals and communities survive the stressful conditions and reproduce to keep the species going. Thus, genetic diversity is a means by which the We will study more about genetic diversity and its aspects in this chapter. What is Genetic Diversity? (Image will be uploaded soon) Genetic diversity indicates a greater number of genetically different individuals within the same species. It is the way by which a population of organisms survives the changing environments. More genetic variation suggests a greater number of individuals with a variety of alleles that help sustain the organisms in the changing Some Attributes of Genetic Diversity • It occurs as a result of gene recombination in the process of inheritance. • Genetic diversity changes with space and time. • One of the key aspects of genetic diversity in sexual reproduction because it produces unique offspring by a combination of parental genes. • Gene mutation, genetic drift, gene flow also lead to genetic diversity. Significance of Genetic Diversity Genetic diversity helps indivi...

David J. Coates 1 *, Margaret Byrne 1 and Craig Moritz 2,3 • 1Biodiversity and Conservation Science, Department of Biodiversity, Conservation & Attractions, Kensington, WA, Australia • 2Division of Ecology & Evolution, Research School of Biology, Australian National University, Acton, ACT, Australia • 3Centre for Biodiversity Analysis, Canberra, ACT, Australia Current approaches to biodiversity conservation are largely based on geographic areas, ecosystems, ecological communities, and species, with less attention on genetic diversity and the evolutionary continuum from populations to species. Conservation management generally rests on discrete categories, such as identified species, and, for threated taxa, intraspecific units. Species, in particular, provide a common measure of biodiversity yet in both theory and nature, speciation is typically a protracted process progressing from connected populations to unambiguous species with variable rates of phenotypic, ecological and genetic divergence. Thus, most recognized species are not genetically uniform and are sometimes highly structured into historically isolated populations worthy of consideration as intraspecific units that represent unique genetic diversity for conservation. Genome screens offer unprecedented resolution of structure across taxonomic boundaries in species complexes, and have the potential to oversplit species if not interpreted conservatively. This highlights the blurred line between populations and spec...

Background Genome-wide association studies have detected a large number of single-nucleotide polymorphisms (SNPs) associated with complex traits in diverse ancestral groups. However, the trans-ethnic similarity and diversity of genetic architecture is not well understood currently. Results By leveraging summary statistics of 37 traits from East Asian ( N max=254,373) or European ( N max=693,529) populations, we first evaluated the trans-ethnic genetic correlation ( ρ g) and found substantial evidence of shared genetic overlap underlying these traits between the two populations, with \(\) ranging from 0.53 (se = 0.11) for adult-onset asthma to 0.98 (se = 0.17) for hemoglobin A1c. However, 88.9% of the genetic correlation estimates were significantly less than one, indicating potential heterogeneity in genetic effect across populations. We next identified common associated SNPs using the conjunction conditional false discovery rate method and observed 21.7% of trait-associated SNPs can be identified simultaneously in both populations. Among these shared associated SNPs, 20.8% showed heterogeneous influence on traits between the two ancestral populations. Moreover, we demonstrated that population-common associated SNPs often exhibited more consistent linkage disequilibrium and allele frequency pattern across ancestral groups compared to population-specific or null ones. We also revealed population-specific associated SNPs were much likely to undergo natural selection compared...

The current record holder, it turns out, may be a mushroom that lives on decayed wood. The lynx, on the opposite end of the spectrum, has very low genetic diversity. That's bad news for the lynx, because having high genetic diversity is advantageous —it basically allows organisms to adapt to changes in their environment. So, what is genetic diversity, and how do species get a lot of it? Essentially, genetic diversity is a measure of how often two bits of DNA from the same genomic location differ from one another within a population, Asher Cutter, a professor in the Department of Ecology and Evolutionary Biology at the University of Toronto, told Live Science. DNA is made up of bases — represented by the letters A, T, C and G — that, together with their backbones, are known as nucleotides. Genetic diversity can be expressed as nucleotide diversity, or the percentage of positions within the genome where two individuals of a given species are expected to have different DNA bases. The split gill mushroom ( Schizophyllum commune) has a nucleotide diversity of up to 20%, according to a 2015 study published in the journal Molecular Biology and Evolution. According to the study, that's the greatest genetic diversity reported for any eukaryote, or organism whose cells have a nucleus. In other words, two different mushrooms will have different DNA bases at about 20 out of every 100 positions in their genomes. That's higher than the genetic diversity of the previous record holder, th...

• Lewontin's paradox — the much larger variation in species abundance than in genetic diversity — is closer to being explained. • The reproductive strategy of species has an impact on genome-wide diversity, providing a connection between population dynamic processes and the long-term effective population size ( N e). • Selection at linked sites also affects genome-wide diversity, but not to an extent that it is sufficient alone to explain Lewontin's paradox. • Selection and demography, among other factors, contribute to variation in N e within genomes and leads to variation in diversity in different genomic regions of the same species. Genetic polymorphism varies among species and within genomes, and has important implications for the evolution and conservation of species. The determinants of this variation have been poorly understood, but population genomic data from a wide range of organisms now make it possible to delineate the underlying evolutionary processes, notably how variation in the effective population size ( N e) governs genetic diversity. Comparative population genomics is on its way to providing a solution to 'Lewontin's paradox' — the discrepancy between the many orders of magnitude of variation in population size and the much narrower distribution of diversity levels. It seems that linked selection plays an important part both in the overall genetic diversity of a species and in the variation in diversity within the genome. Genetic diversity also seems to ...