Another interesting paper -- this one I may actually study in detail in the future to see if I may reproduce their conclusions as it does deal w/STRs A couple of exerpts: "Finally, the question was addressed of how closely related selected source and migrant populations might be in terms of their extant Y-STR haplotype spectra. A comparison between Han Chinese from Colorado (USA) and Han Chinese from Beijing, Chengdu (both China) and Singapore, respectively, yielded non-significant PPY23-based RST (-0.002, 0.007 and 0.004). In strong contrast, African Americans from Illinois, the Southwest and the whole of the US were quite distant to Africans from Ibadan (Nigeria) (RST= 0.10, 0.12 and 0.09, respectively). Although likely not to represent the true source population, the distance between a group of Tamil from India and the Texan Gujarati population was as low as RST=0.008, while the distance between the Tamils and a migrant Indian population in Singapore equalled 0.03. Finally, the distance between European Americans from Illinois, Utah and the whole USA on the one hand, and the Irish on the other, was found to be consistently small (RST=0.01, 0.04 and 0.02, respectively). A similar trend applied to other European source populations and to European migrant populations in South America. Thus, Argentineans of European ancestry from Buenos Aires, Formosa, Mendoza and Neuquen showed virtually zero genetic distance to Spaniards from Galicia (all three pairwise RST∼0)." "The present study revealed a considerable number of null and duplicated alleles that were caused either by non-allelic homologous recombination between paralogous DNA sequences [35] or–in the case of nulls–by deletions or primer site mutations [36]. Compared to Yfiler, the PPY23 allelic ladder has been enriched with new length variants to accommodate the various intermediate alleles that were observed as well. Previous population genetic analyses consistently revealed that Y-chromosomal haplotypes have a highly non-uniform geographical distribution characterized by less variation within, and more variation between, population groups than autosomal markers [37]. This difference has been explained by (i) the smaller effective population size of Y chromosomes causing stronger genetic drift, and (ii) haplotype clustering due to widespread patrilocality. Therefore, population structure, will be more pronounced in Y-chromosomal genetic databases and must be taken into account when database counts are used to quantify the evidential value of matches in forensic casework [38]. It has been shown, however, that so-called meta-populations may be constructed for Y-STRs that have low haplotypic variation among population groups within a meta-population, but large variation between meta-populations [39]. If necessary, such meta-populations can be defined ab initio using geography as a proxy of genetic relatedness, or by taking ethnic or linguistic data into account."