Today, as the stock of available reagents is almost depleted, the ‘GM story’ is coming to an end unless precise GM DNA typing becomes possible. The GM haplotypes are combinations of GM allotypes of different IgG sub-classes. As a result of the close linkage, on the long arm of chromosome 14 (14q32.33), of the genes coding for the this website constant domains of the heavy chains of immunoglobulins (the IGCH genes), the genetic transmission of IgG allotypes occurs through GM haplotype blocks (recombinations occur but are rare). Table 1 lists the most frequent haplotypes found in human populations.4,12 Note, however,

that the GM polymorphism was primarily analysed in the 1970s, and GM haplotypes have generally been deduced ‘by hand’ from GM phenotypes because of the absence, at that time, of accurate genotyping techniques and the lack of available frequency estimation programs accommodating ambiguities. Therefore, there has certainly been some bias towards an over-estimation of the frequency of the most frequent haplotypes found in human populations. The GM haplotypes have proven to be very useful for anthropology. There are striking differences in GM haplotype frequencies among populations from different geographic areas.4,12 www.selleckchem.com/products/Romidepsin-FK228.html If the highest resolution level is omitted (i.e. haplotypic subdivisions on the basis of the presence/absence of allotypes G2M 23 and G1/3M 28, which have

seldom been tested at the global level), very high frequencies are found for GM 3 5* (where 5* stands for 5,10,11,13,14)

in Europeans, North Africans and Southwest Asians, GM 1,17 5* in sub-Saharan Africans and some North Africans, GM 1,3 5* in Southeast Asians and some Oceanian populations, GM 1,17 21 in Europeans, Northeast Asians, Amerindians and some Oceanian populations (and sometimes in other regions), and GM 1,2,17 21 in Northeast Asians and South Amerindians (Table 1). G2M 23 further subdivides haplotype GM 3 5* in two sub-haplotypes, GM 3 (–23) 5* and GM 3 23 5*, with variable frequencies in Europe. In sub-Saharan Africa, GM 1,17 5* (without G2M 23) seems to be predominant (as far as G2M 23 has been tested). In Asia GM 1,3 23 5* is the most frequent form. Some Papuan populations from New Guinea and Molecular motor Australian Aborigines exhibit haplotype GM 1,17 23 5*, thereby differing from GM 1,17 (-23) 5*, which is frequently found in Africa. Other haplotypes are principally found at regional levels, like GM 1,17 5,6,11,24, GM 1,17 5,6,10,11,14 and GM 1,17 10,11,13,15 in sub-Saharan Africa (the latter being frequent in the Khoisan), and GM 1,17 10,11,13,15,16 in Northeast Asian and Circum-Arctic populations. However, most haplotypes are found at low frequencies in different geographic regions. For example, GM 1,17 21 and GM 1,2,17 21 are universal (although with variable frequencies), and GM 1,17 5* is commonly observed in populations with different origins.