Aggarwal Aastha, Gauniyal Mansi, Pattanayak Ipsa, Kshatriya Gautam K
Department of Anthropology, University of Delhi (North Campus), Delhi-110 007, India.
Indian J Hum Genet. 2010 May;16(2):55-60. doi: 10.4103/0971-6866.69327.
Dopamine receptor D2 (DRD2) is an important gene having functional significance in the fields of neuropsychiatry and pharmacology and also has importance in evolutionary studies.
This study was undertaken to find out the haplotype distribution and linkage disequilibrium (LD) pattern for the three TaqI sites (TaqI 'A', TaqI 'B' and TaqI 'D') in the DRD2 gene in 232 unrelated individuals from five ethno-linguistically distinct endogamous tribal populations; Siddis and Gonds of Uttara Kannada district, Karnataka; Varli and Kolgha of Valsad district, Gujarat; and Dangi Konkana of Dang district, Gujarat. The genotype data obtained after molecular analysis of the three DRD2 sites was subjected to statistical analysis such as calculation of allele frequencies, haplotype frequencies among others. Subsequently, a neighbor-joining tree was also constructed from the data obtained.
The three DRD2 sites were found to be polymorphic in all the populations. All the populations showed high levels of heterozygosities. Out of the eight possible haplotypes, most populations shared seven haplotypes. Of all the populations, Siddis showed the highest frequency of the ancestral haplotype B2D2A1 (11.4%). Significant LD was found to exist for TaqI 'A' and TaqI 'B' sites in both the populations.
The findings are in concurrence with those from other Indian studies, especially from Dravidian-speaking South Indian populations. Similar pattern of diversity observed for ethnically and linguistically diverse populations in the present study is indicative of complex structure of Indian populations.
多巴胺受体D2（DRD2）是一个在神经精神病学和药理学领域具有功能意义的重要基因，在进化研究中也具有重要性。
本研究旨在找出DRD2基因中三个TaqI位点（TaqI'A'、TaqI'B'和TaqI'D'）在来自五个语言和族裔不同的内婚制部落群体的232名无关个体中的单倍型分布和连锁不平衡（LD）模式；卡纳塔克邦北卡纳达区的西迪族和贡德族；古吉拉特邦瓦尔萨德区的瓦尔利族和科尔加族；以及古吉拉特邦当区的丹吉孔卡纳族。对三个DRD2位点进行分子分析后获得的基因型数据进行了统计分析，如计算等位基因频率、单倍型频率等。随后，还根据获得的数据构建了邻接树。
发现这三个DRD2位点在所有群体中均为多态性。所有群体均表现出高杂合度。在八种可能的单倍型中，大多数群体共享七种单倍型。在所有群体中，西迪族显示出祖先单倍型B2D2A1的最高频率（11.4%）。在两个群体中，均发现TaqI'A'和TaqI'B'位点存在显著的LD。
这些发现与其他印度研究的结果一致，特别是来自说达罗毗荼语的南印度群体的研究。本研究中在种族和语言多样的群体中观察到的类似多样性模式表明印度群体结构复杂。
