Y‐chromosome and mitochondrial DNA studies on the population structure of the Christmas Island community

Abstract

Christmas Island is a remote Australian territory located close to the main Indonesian island of Java. Y-chromosome and mitochondrial DNA (mtDNA) markers were used to investigate the genetic structure of the population, which comprises communities of mixed ethnic origin. Analysis of 12 Y-chromosome biallelic polymorphisms revealed a high level of gene diversity and haplotype frequencies that were consistent with source populations in southern China and Southeast Asia. mtDNA hypervariable segment I (HVS-I) sequences displayed high levels of haplotype diversity and nucleotide diversity that were comparable to various Asian populations. Genetic distances revealed extremely low mtDNA differentiation among Christmas Islanders and Asian populations. This was supported by the relatively high proportion of sequence types shared among these populations. The most common mtDNA haplogroups were M* and B, followed by D and F, which are prevalent in East/Southeast Asia. Christmas Islanders of European descent were characterized by the Eurasian haplogroup R*, and a limited degree of admixture was observed. In general, analysis of the genetic data indicated population affinities to southern Chinese (in particular from the Yunnan Province) and Southeast Asia (Thailand, Malaysia, and Cambodia), which was consistent with historical records of settlement. The combined use of these different marker systems provides a useful and appropriate model for the study of contemporary populations derived from different ethnic origins.

Genetic diversity of two haploid markers in the Udegey population from southeastern Siberia

“…The genetic structure of the Udegeys and the Eurasian reference populations was further investigated by AMOVA (Excoffier et al, 1992) (Table 5). For mtDNA haplogroups and HVS-1 sequences data, the lower interpopulation variances in East Asia than those of south Siberia/Europe suggest greater homogeneity of East Asian populations (Jorde et al, 2000;Wise et al, 2005). For Y chromosome data, the level of between-population differentiation was much higher than for mtDNA, which is consistent with earlier reports (Nasidze et al, 2005;Jin et al, 2009).…”

Genetic ancestries in northwest Cambodia

“…These are the most common reported maternal haplogroups throughout the region (Thangaraj et al 2005b;Wen et al 2005;Wise et al 2005). The additional presence of haplogroup D suggested ancestral influence from China (Wen et al 2004).…”

“…Additionally, R1a1* is present in Bali, with an Indian origin postulated (Karafet et al 2005). This haplogroup was, however, also present in three individuals of European descent resident on Christmas Island, which is located to the southwest of the main Indonesia island of Java (Wise et al 2005).…”

“…The mtDNA hypervariable segment I (HVS I) was amplified and sequenced in a representative sub-group of 31 individuals according to methods developed and outlined in Wise et al (2005). The individuals were also screened for the mtDNA 9-bp deletion in the COII/tRNA Lys intergenic region (Qian et al 2001).…”

“…Y-chromosome and mtDNA haplogroup frequencies in the Cambodian population were compared with those in six divergent Chinese communities (Black et al 2001, in press;Wang et al 2003) and in the South and Southeast Asian population of Christmas Island (Wise et al 2005). In addition, the Y-chromosome data were compared with populations in Northeastern Thailand and Malaysia (Su et al 1999), Bali (Karafet et al 2005), and Southern Han Chinese (Karafet et al 2001).…”