Morizot D C, Siciliano M J
Genetics. 1979 Dec;93(4):947-60. doi: 10.1093/genetics/93.4.947.
Electrophoretic variants at four additional enzyme loci--two esterases (Est-2, Est-3), retinal lactate dehydrogenase (LDH-1) and mannose phosphate isomerase (MPI)--among three species and four subspecies of fish of the genus Xiphophorus were observed. Electrophoretic patterns in F1 hybrid heterozygotes confirmed the monomeric structures of MPI and the esterase and the tetrametric structure of LDH in these fishes. Variant alleles of all four loci displayed normal Mendelian segregation in backcross and F2 hybrids. Recombination data from backcross hybrids mapped with Haldane's mapping function indicate the four loci to be linked as Est-2--0.43--Est3--0.26--LDH-1--0.19--MPI. Significant interference was detected and apparently concentrated in the Est-3 to MPI region. No significant sex-specific differences in recombination were observed. This group (designated linkage group II) was shown to assort independently from the three loci of linkage group I (adenosine deaminase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase) and from glyceraldehyde-3-phosphate dehydrogenase and two isocitrate dehydrogenase loci. Evidence for conservation of the linkage group, at least in part, in other vertebrate species is presented.
在剑尾鱼属的三个物种和四个亚种的鱼类中，观察到另外四个酶位点的电泳变异体，即两种酯酶（Est-2、Est-3）、视网膜乳酸脱氢酶（LDH-1）和磷酸甘露糖异构酶（MPI）。F1杂交杂合子的电泳图谱证实了这些鱼类中MPI和酯酶的单体结构以及LDH的四聚体结构。所有四个位点的变异等位基因在回交和F2杂种中均表现出正常的孟德尔分离。利用霍尔丹作图函数对回交杂种进行重组数据作图，结果表明这四个位点的连锁关系为Est-2--0.43--Est3--0.26--LDH-1--0.19--MPI。检测到显著的干扰，且明显集中在Est-3至MPI区域。未观察到重组存在显著的性别特异性差异。该组（指定为连锁群II）被证明与连锁群I的三个位点（腺苷脱氨酶、葡萄糖-6-磷酸脱氢酶和6-磷酸葡萄糖酸脱氢酶）以及甘油醛-3-磷酸脱氢酶和两个异柠檬酸脱氢酶位点独立分配。本文提供了至少部分连锁群在其他脊椎动物物种中保守的证据。
