Population genetics study is based on that in different population's maps the frequency of various inherited properties, particularly particular affection's hijacker. It turns out that race differences largely depending on the alleles in single ticket systems have different frequencies in ethnically or geographically separate populations, and not due to the absolute absence or presence of "specific alleles" in one or the other population. Equality / inequality in gene frequencies has been used to determine the different population groups' relationship to each other, but it has also been shown that random fluctuations (genetic drift) and environmental factors (eg. Malaria: selection) can play a definite role in origins of inequality in gene frequencies. Cloning of genes and direct detection of rare mutations have led to that one can follow certain genes in populations and migration between countries more on this topic during genetic epidemiology.
The study of mitochondrial DNA has given strong support to the theory that Homo sapiens lived in Africa for at least 100 000 years and that maybe for some. 40 000 years ago a small group through the Middle East spread to Asia and Europe a long way more information about the history obtained by testing normal DNA markers around the unique mutations, the so-called haplotype analysis. That is how much you go down the DNA string that determines how far back in time you will get the story.
At the international "human diversity" project aims at collecting samples for DNA analysis of as many groups of people who have lived long, more or less isolated, in a place before isolates are completely dissolved. More marriages between counties rather than in the home county have led to a decline in rare recessive diseases. This reflects that we are probably descended from several different immigrant populations in the 10,000 years it has actually lived people in the country older people with mainly local ancestors in their DNA an information that will stretch far beyond the topical history books-in range. It is here in the order of the alleles in all DNA markers along the chromosome strings, which requires samples from two generations.
