METHODS: We analyzed the association between ethnic as well as religious homogamy and woman's average number of offspring based on census data from ten countries provided by IPUMS international, encompassing a total of 1,485,433 married women aged 46-60 years (who have thus completed or almost completed reproduction) and their spouses.
RESULTS: We find a clear pro-fertile but nonadditive effect of both ethnic and religious homogamy, which is most pronounced in the case of double homogamy. Our results further indicate that homogamy for one trait may compensate for heterogamy of the other, albeit countries differ regarding which trait compensates for the other.
CONCLUSIONS: We suggest that the interaction between ethnic homogamy, religious homogamy, and reproduction provides an interesting example for gene-culture co-evolution.
METHODS: KIR genotyping for 213 unadmixed Malay individuals from six subethnic groups (Acheh, Bugis, Champa, Mandailing, Minang and Kedah) was carried out using PCR-SSP (sequence specific primers) method in 16 independent reactions.
RESULTS: The most frequent KIR genotype observed is AA1, followed by AB4 and AB5. Five genotypes; AA1, AB4, AB5, AB7 and AB8 were shared among all Malay subethnic groups. The highest frequency of KIR haplotype A was observed in Minang Malays, whereas Acheh and Kedah Malays carry a balanced distribution of A and B KIR haplotypes. PCA for the KIR genes clearly illustrated six ethnogeographical population clusters; Africans, Amerindian, Northeast Asian, South Asian, Oceania and Southeast Asian populations. All six Malay subethnic groups fell within the Southeast Asian cluster.
CONCLUSIONS: The complex array of KIR genotypes observed in the Malays indicates their historical interactions with various populations, especially with the Chinese, Indians and Orang Asli. This study has demonstrated the potential of KIR genes as a genetic marker for deducing population structure and genetic relationship between populations.