Shields G F, Gust J R
Institute of Arctic Biology, University of Alaska, Fairbanks 99775-7000, USA.
Mol Mar Biol Biotechnol. 1995 Mar;4(1):69-82.
We compared 511 nucleotides of mitochondrial DNA from 162 walleye pollock from 32 locations in the Bering Sea, the Shelikof Strait, and the Gulf of Alaska to learn about population structuring in this economically important species. Specifically, we tested for evidence of genetic heterogeneity among three sequence data sets: a 76-bp spacer, the control region, and spacers and control regions combined among six geographic regions: southwest Bering Sea, northern Bering Sea, western Aleutians, eastern Aleutians, the Donut Hole, and the Gulf of Alaska. No significant genetic heterogeneity was detected among spacer sequences or control regions, or spacers and control regions combined among areas of the Bering Sea. Slight genetic heterogeneity was detected when a "Western Bering" sample (southwest Bering and northern Bering) and an "Eastern Bering" sample (western Aleutians and eastern Aleutians) were compared. Presence of an abundant and widespread haplotype suggests recent establishment of the walleye pollock population in the Bering Sea. However, the ratio of nucleotide transitions to transversions in these pollock is extremely low, suggesting that the population may be old. Presence of a widespread and abundant haplotype, together with numerous rare ones, suggests a high variance in reproductive success for relatively few females, which may be disproportionately contributing to the survival of individual haplotypes. Sequencing of control regions in pollock may be less informative than conventional analysis of restriction fragment length polymorphisms or RFLP analysis of amplified variable sites.
我们比较了来自白令海、舍利科夫海峡和阿拉斯加湾32个地点的162条狭鳕鱼线粒体DNA的511个核苷酸，以了解这个具有重要经济价值的物种的种群结构。具体而言，我们在三个序列数据集（一个76碱基对的间隔区、控制区以及间隔区和控制区的组合）中测试了六个地理区域（白令海西南部、白令海北部、阿留申群岛西部、阿留申群岛东部、“甜甜圈洞”区域以及阿拉斯加湾）之间遗传异质性的证据。在白令海各区域的间隔区序列、控制区或间隔区与控制区的组合中均未检测到显著的遗传异质性。当比较“白令海西部”样本（白令海西南部和白令海北部）和“白令海东部”样本（阿留申群岛西部和阿留申群岛东部）时，检测到了轻微的遗传异质性。一种丰富且广泛分布的单倍型的存在表明狭鳕鱼种群在白令海是近期形成的。然而，这些狭鳕鱼中核苷酸转换与颠换的比率极低，这表明该种群可能很古老。一种广泛且丰富的单倍型与众多罕见单倍型的存在表明，相对较少的雌性在繁殖成功率上存在很大差异，这可能对各个单倍型的存活有不成比例的贡献。对狭鳕鱼控制区进行测序可能不如对限制性片段长度多态性进行传统分析或对扩增可变位点进行RFLP分析提供的信息多。
