| 摘要: |
| 1995年1月–1996年12月，采用水平淀粉凝胶电泳技术，对美国海湾扇贝5个野生种群和1个养殖种群在磷酸葡萄糖变位酶基因位点（Pgm）的遗传结构及相关性状进行了分析，共发现7个等位基因。MV（Marthas Vineyard Island）、NY（Long Island）、CT（Stonington）种群间等位基因频率分布无显著差异，内湾封闭性环境和人工近亲繁殖分别使WF（Wellfleet）、CN（养殖种群）等位基因频率分布产生显著分化，杂合性降低。CN种群呈现遗传退化，仅4个等位基因。NC（Beaufort）等位基因频率分布显著区别其它种群，其肋条数和形态特征指数所H／L、H／Wd（H:壳高，L：壳长，Wd：壳宽）显著高于其它种群，Pgm等位基因频率存在南北向梯度分布。Pgm基因位点存在偏离Hardy－Weinberg遗传平衡现象，Pgm83具显著的纯合子过剩现象，纯合子大于其它基因型。种群CT、NC、WF的Pgm100，MV、CT、NC的Pgm93及WF的Pgm78存在显著纯合子过剩现象。NC、CN与其它种群具显著种群间遗传差异，NC种群杂合子的壳长、高、宽及体重普遍大于纯合子，且杂合子Pgm100/78壳长明显高于纯合子Pgm100/100。而其它种群杂合子个体的壳长、宽、高及体重普遍低于纯合子。 |
| 关键词: 海湾扇贝 同工酶 种群遗传 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金资助项目，39470106号;国家攀登计划B资助，PDB－6－5－3号 |
|
| POPULATION GENETIC STRUCTURE AT ALLOZYME PHOSPHOGLUCOMUTASE PGM LOCUS AND ITS RELATED TRAITS IN DIFFERENT POPULATIONS OF BAY SCALLOP, ARGOPECTEN IRRADIANS |
|
XUE Qin-zhao1, Sheila Stiles2, ZHANG Fu-sui1, XIANG Jian-hai1
|
|
1.Institute of Oceanology, The Chinese Academy of Sciences, Qingdao, 266071;2.NOAA, National Marine Fisheries Service, Milford Laboratory, Milford CT06460, USA
|
| Abstract: |
| From January 1995, to December 1996, population genetic at the locus of allozyme phosphoglucomutase (PGM) and its related traits in 6 different populations of bay scallop, Argopecten irradians were investigated using horizontal starch gel electrophoresis method. These include populations from MV (Marthas Vineyard, MV), NY (Long Island, NY), CT (Stonington, CT), WF (Wellfleet, MA), NC (Beaufort, NC) and CN (artificially cultured population). Totally 7 alleles, Pgm104, Pgm100, Pgm93, Pgm88, Pgm83, Pgm78 and Pgm76 at Pgm locus are found in bay scallop, A. irradians. No significant difference if allele frequency distribution at Pgm locus is observed among populations of MV, NY and CT. The sheltered sedimentary environment in WF population and artificially inbreeding manipulation in CN populations, respectively, and result in the decrease of heterozygosities in WF and CN compared with other populations. NC population demonstrates a significantly different allele frequency structure at Pgm locus from the other populations and its rib number and morphological indexes H/L and H/Wd (H: shell height, L: shell length, Wd: shell width) are significantly greater than the other populations investigated. This observation indicates that NC population is the southern warm subspecies A. i. concertricus and the other populations are the northern temperate subspecies A, i. irradians. From the North to South, allele Pgm100 frequency decreases gradually in MV, NY, CT and NC populations, whereas allele Pgm83 frequency increases gradually. Remarked deviations from Hardy-Weinberg equilibrium and heterozygote deficiency are observed at Pgm locus. Analysis using Wrights Fixing Index indicates that significant homozygote excess at allele Pgm83 appears in all 6 populations investigated and Pgm83 homozygotes generally show a greater individual size compared with the other Pgm genotype individuals. Significant homozygote excess is also observed with Pgm100 in CT, NC and WF populations, Pgm93 in MV, CT and NC populations as well as Pgm78 in WF population. An analysis of population genetic distance and identity demonstrates that significant interpopulation genetic difference exists between NC, CN and the other population, whereas no such difference is found among MV, NY and CT. In the NC population, the shell height, length, width and weight of heterozygotes are generally larger than those of homozygotes and the shell length of heterozygote Pgm100/78 is significantly larger than homozygote Pgm100/100. In the other 5 populations, no significant correlation between heterozygotes and growth is found and the shell length, height, width and weight of heterozygotes are generally smaller than those of homozygotes. This may be due to the fact that heterozygotes of bay scallop, A, i. irradians invest too much energy into predator escape activities instead of somatic growth. |
| Key words: Bay scallop Argopecten irradians, Allozyme, Population genetics |
