Since their emergence as a national and religious group in the Middle East over 2,000 years ago (Biran and Naveh 1993), Jews have maintained continuous cultural and religious traditions amid a series of Diasporas (Ben-Sasson 1976).
Along the way, others were converted into the Jewish fold. The origins and relatedness of the various Jewish groups have been much speculated upon over the past century.
Jews have described themselves as a “people”, based on their shared religion, without a clear indication of the genetic lines of descent since their early history.
Albert Einstein captured this uncertainty when he wrote to the Berlin rabbis in 1921 “I notice that the word Jew is ambiguous in that it refers (1) to nationality and origin, (2) to the faith” (Einstein et al. 1987).
With the advent of modern population genetics based on analysis of genetic markers in the second half of the twentieth century, investigators have attempted to categorize the origins and relatedness of Jewish people.
Because relatively few polymorphic markers were available at first, the early studies focused on genetic distances between groups and established hierarchies based on these distances (Bonne-Tamir et al. 1978a, b, 1977; Carmelli and Cavalli-Sforza 1979; Karlin et al. 1979; Kobyliansky et al. 1982; Livshits et al. 1991).
Population genetics has been enhanced by the identification of millions of polymorphic markers that reside in close proximity to one another along the genome and that vary in their allele frequencies among populations.
These discoveries have led to greater precision for estimates of genetic distances. These discoveries have also led to new types of analyses that were not available in the past.
The analyses have included deconvolution of ancestry for whole genomes or for segments of individual genomes and analysis of segmental sharing among individuals that provide greater accuracy for estimating their degree of relatedness (Atzmon et al. 2010; Bryc et al. 2010)…
Note: Not new (from 2012) but interesting. The article is available for the general public to read.
I found it at recent New York Times article that is interesting in itself: A New Theory on How Neanderthal DNA Spread in Asia. Also of interest is an article on the Amish.
I also recommend another recent NYT article: Two Strains of H.I.V. Cut Vastly Different Paths