It’s a racist thing to say but you know, to Europeans all Chinese look the same, and to Chinese they find it very hard to tell your appearance apart quite often. The effect of this assortative mating is to reduce gene flow between geographical groups and to increase the genetic distance between groups.  Phenotype is connected to genotype through gene expression. A more realistic approach is to understand that some human groups are parental to other groups and that these groups represent paraphyletic groups to their descent groups. This translates to an estimated 85% of the variation measured in the overall human population is found within individuals of the same population, and about 15% of the variation occurs between populations. This is because of their genetic individuality. Environmental changes that are natural or due to human intervention, lead to the natural selection and survival of the fittest. As a result of variation in frequencies of both genetic and nongenetic risk factors, rates of disease and of such phenotypes as adverse drug response vary across populations. Groups of chimpanzees within central Africa are more different genetically than humans living on different continents, an Oxford University-led study has found. These are genuinely astronomical figures about human difference, and they arise from the fact that through the three thousand million bases of DNA there are something like three million at a rough guess sites which very can vary from one person to another. For example, ~90% of the variation in human head shapes occurs within continental groups, and ~10% separates groups, with a greater variability of head shape among individuals with recent African ancestors (Relethford 2002).  Hammer et al. And they said, prove the idea. What that tells us is something we know already from the fossil record: that every one of us across the world is an African. Human population density and land use is causing changes in animal genetic diversity, according to researchers at McGill University. For example, animals can be carriers of a gene for an inherited disease, but not show any symptoms. We are an African species of primate which got out of Africa really relatively recently. African-American populations have been the focus of numerous population genetic and admixture mapping studies, including studies of complex genetic traits such as white cell count, body-mass index, prostate cancer and renal disease. The greatest divergence between populations is found in sub-Saharan Africa, consistent with the recent African origin of non-African populations. Therefore, the mutation on CCR5 gene decreases the chance of an individual's risk with AIDS. They find that the figure of 85% is misleading because it implies that all human populations contain on average 85% of all genetic diversity. Genetic data can be used to infer population structure and assign individuals to groups that often correspond with their self-identified geographical ancestry. If we consider an organism with higher diversity of genes, it implies that it has a higher chance of utilizing its diverse gene pool and adapting itself to change along with its changing environm… About 3% to 5% of human SNPs are functional (see International HapMap Project). 2004). Some researchers argue that self-identified race can be used as an indicator of geographic ancestry for certain health risks and medications. The recent African origin of modern humans paradigm assumes the dispersal of non-African populations of anatomically modern humans after 70,000 years ago. Since then we’ve moved across the world and filled it, and we haven’t really changed very much in that time. The distribution of genetic variants within and among human populations are impossible to describe succinctly because of the difficulty of defining a "population," the clinal nature of variation, and heterogeneity across the genome (Long and Kittles 2003). Of course, enzymes are made of proteins, they’re made of amino acids, they’re folded with little machines that can chew different chemical substances, and amino acids have charged molecules so that any difference in the order of the amino acids in that enzyme is liable to change the amount of charge on it which may also change the shape of the molecule and might also change the size of the molecule. If th… There may be multiple variants of any given gene in the human population (alleles), a situation called polymorphism. So this is the first insight of the hidden genetic variation. Neanderthal of 50k  has been built by Pratas et al. , An analysis of autosomal SNP data from the International HapMap Project (Phase II) and CEPH Human Genome Diversity Panel samples was published in 2009. Genetic diversity is important for two reasons. , Neil Risch of Stanford University has proposed that self-identified race/ethnic group could be a valid means of categorization in the US for public health and policy considerations. , Between 4% and 6% of the genome of Melanesians (represented by the Papua New Guinean and Bougainville Islander) are thought to derive from Denisova hominins – a previously unknown species which shares a common origin with Neanderthals. Genetic diversity refers to the diversity (or genetic variability) within species.  Other sequence variations are single base exchanges, deletions and insertions. According to a 2000 study of Y-chromosome sequence variation, human Y-chromosomes trace ancestry to Africa, and the descendants of the derived lineage left Africa and eventually were replaced by archaic human Y-chromosomes in Eurasia. It’s not quite like that but every time sex takes place, these cars are reshuffled and they come in two new combinations. The person who founded our laboratory, Francis Galton (Charles Darwin’s cousin) was in some ways the founder of human genetics because he wrote a book about the inheritance of genius. Serial founder effects and past small population size (increasing the likelihood of genetic drift) may have had an important influence in neutral differences between populations. The variability of a trait is how much that trait tends to vary in response to environmental and genetic influences. , Thus, Melanesians emerge as the most archaic-admixed population, having Denisovan/Neanderthal-related admixture of ~8%. A single nucleotide polymorphism (SNP) is a difference in a single nucleotide between members of one species that occurs in at least 1% of the population. …  Another study shows an increased risk of graft-versus-host disease complications after transplantation due to genetic variants in human leukocyte antigen (HLA) and non-HLA proteins. In May 2010, the Neanderthal Genome Project presented genetic evidence that interbreeding did likely take place and that a small but significant portion, around 2-4%, of Neanderthal admixture is present in the DNA of modern Eurasians and Oceanians, and nearly absent in sub-Saharan African populations. Genetic variation among humans occurs on many scales, from gross alterations in the human karyotype to single nucleotide changes. 2004), these estimates may assume a false distinctiveness of the parental populations, since human groups have exchanged mates from local to continental scales throughout history (Cavalli-Sforza et al. 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