Forensic parameters of 19 X-STR polymorphisms in two Chinese populations

Abstract

Application of X-STRs as complements of autosomal STR application in the forensic genetics has become a tendency for kinship testing, especially in deficiency paternity cases. Recently, a novel kit of 19 X-STR loci was developed, which permitted the analysis of 19 STR in the same PCR reaction, and these markers can be clustered into seven groups for the physical linkage. The objective of this study was to evaluate the allele and haplotype diversity of 19 X-STR loci in the Uygur (n = 220) and Tibetan nationality (n = 270) and to estimate the usefulness for complex kinship analysis. In the Tibetan and Uygur populations, a total of alleles of all loci were 188 and 212, with the allele frequencies ranged from 0.0037 to 0.5593 and from 0.0045 to 0.5409, respectively. Compared with previous studies, DXS10135 was the most polymorphic locus in the two population groups, whereas the least variant locus was DXS10164 in the Uygur population and DXS7423 in the Tibetan nationality. Haplotype diversity obtained in this investigation was greater than 0.9 across all LGs. This study indicated the new kit could be used as a supplementary tool in kinship testing in China. In addition, the data sets can be used as supplementary national X-STR references to enlarge the database.

Forensic characterization and genetic polymorphisms of 19 X-chromosomal STRs in 1344 Han Chinese individuals and comprehensive population relationship analyses among 20 Chinese groups

“…China, composed of 56 officially recognized ethnic groups and a population over 1,404 billion, harbors substantial genetic, linguistic, physical, cultural and diversity [ 30 , 31 ] (1.2 billion Hans, 10.5 million Huis, 10 million Uyghurs, 9.4 million Miaos, 8.7 million Yis, 6.2 million Tibetans, 1.4 million Lis, 1.4 million Kazakhs, 0.55 million Gelaos, 0.19 million Xibes, and others ( https://en.wikipedia.org/wiki/Han_Chinese ). Here, to implement X-STR typing into routine forensic practice and establish Chinese reference database as well as investigate genetic diversity and forensic characteristics of Han Chinese population, we newly generated 19 X-STRs data from 206 Guizhou Han subjects ( S1 Table ) and combined previously published 4868 genotypes [ 19 – 27 , 29 ], the dataset from 20 Chinese populations belonging to four language families: Sino-Tibetan includes Sinitic branch (Han [ 22 , 25 , 26 ] and Hui [ 25 ]) and Tibeto-Burman branch (Tibetan [ 20 , 25 , 27 ], Yi [ 19 ]); Tai-Kadai (Gelao, Li); Hmong-Mien (Miao [ 29 ]); Altaic comprises Turkic (Uyghur [ 20 , 21 , 25 ], Kazakh [ 23 ]), Tungusic (Xibe [ 24 ]). To characterize the genetic diversity of Han Chinese population, we then obtained 1344 genotypes of 19 X-chromosomal STRs in Han Chinese population from four different geographical administrations (Guizhou: 206, Sichuan [ 22 ]: 201, Hainan: 155, Guanzhong [ 26 ]: 474 and South China [ 25 ]: 308).…”

“…We then combined in total of 3730 previously reported genotypes from 15 different populations [ 20 , 21 , 23 – 25 , 27 – 29 ] to investigate genetic relationships within and between Han Chinese populations and other ethnic groups along ethnic, linguistic and geographical divisions, which consist of two Sinitic-speaking populations (191 Wuzhong Huis (44 females and 147 males) and 200 Huis (68 females and 132 males) from Ningxia Hui autonomous region), two Tai-Kadai-speaking populations (513 Gelaos (265 females and 248 males) from Guizhou province and 167 Lis (108 females and 59 males) from Hainan province), four Turkic-speaking population (300 Ili Kazakhs (151 females and 149 males), 220 Xinjiang Uyghur males, 233 Ili Uyghurs (139 females and 94 males) and 211 Korla Uyghurs (66 females and 145 males) from Xinjiang Uyghur autonomous region), one Hmong-Mien-speaking population (268 Zunyi Miaos from Guizhou province), one Tungusic-speaking population (179 Ili Xibes (92 females and 87 males) from Xinjiang Uyghur autonomous region), and five Sino-Burman-speaking populations (331 Liangshan Yis (198 females and 133 males), 199 Dujiangyan Tibetans (103 females and 96 males) and 235 Muli Tibetans (118 females and 117 males) from Sichuan province; and 270 Tibet Tibetan males).…”

“…We used the Reynolds’s and Nei’s pairwise genetic distances, as well as Fst and corresponding p values to estimate the genetic differences and similarities using the PHYLIP version 3.5 packages [ 40 ] and Arlequin software (version 3.5.2) [ 32 ]. We first compared the genetic relationships of Guizhou Han and other four Han Chinese populations from different geographical regions [ 22 , 25 , 26 ] as well as other 15 Chinese previously published minorities [ 20 , 21 , 23 – 25 , 27 – 29 ]. And then we investigated the genetic relation between the Meta-Han and other 15 reference populations [ 19 – 27 , 29 ].…”

“…To get a more complete picture of human X-chromosomal STRs of in China (especially for Han Chinese population), we genotyped 206 Guizhou Han individuals using AGCU X19 system and merged our newly-generated dataset with four publically available datasets of Han Chinese populations from different administrative divisions [ 22 , 25 , 26 ] (Dataset Ⅰ referred to as Meta-Han Chinese population consisting of 1344 individuals). We also merged our dataset with data from other 15 populations belonging to other language families (Dataset Ⅱ comprises 5074 Chinese individuals) [ 20 , 21 , 23 – 25 , 27 – 29 ] to investigate the genetic relationships between Han or Meta-Han Chinese population and other Chinese minority groups.…”

Analyzing an “Off-Ladder” allele at DXS10135 from the AGCU X19 STR kit

“…Because of great advantages in sibship determination, mother-son kinship determination and grandmother-granddaughter relationships [1,2], X-STRs have been expected to play an important role in complex kinship analyses and become a hot research topic in recent years [3]. In this sense, a commercial X-STRs kit named AGCU X19 STR Kit, was widely used in China [1,4]. During studies on X-STRs using AGCU X19 STR Kit, an unusual "Off-ladder" allele between allele 21 and allele 21.1 at DXS10135 was detected in the electropherogram.…”