Department of Animal Biology, Faculty of Biology, University of Barcelona, 645 Diagonal Ave, 08028 Barcelona, Spain.
Mol Ecol. 2010 Feb;19(3):484-93. doi: 10.1111/j.1365-294X.2009.04506.x. Epub 2010 Jan 8.
Some species of sea urchins feature large variation in pigmentation. This variability may be the result of phenotypic plasticity or it may be associated with genetic divergence between morphs. Paracentrotus gaimardi exhibits five colour morphs (pink, brown, green, grey and black), which often occur side by side on the same rock. We studied genetic divergence between these morphs in three populations on the coast of Brazil. A fragment of the region encoding the mitochondrial ATPase 8 and 6 mitochondrial genes, a fragment of the intron of a nuclear histone and the entire nuclear gene coding for the sperm protein bindin were analysed. Mitochondrial DNA was differentiated between the pink and all other morphs, but the histone intron was similar in all colour morphs. In bindin, nine codons were found to be under positive selection and significant differences of allelic frequencies were observed in almost all pairwise comparisons between colour morphs. Although the molecular differentiation in bindin is not large enough to suggest reproductive isolation, some degree of assortative mating within morphs seems to be occurring in this species.
一些种类的海胆在色素沉着方面表现出很大的变化。这种可变性可能是表型可塑性的结果，也可能与形态之间的遗传分歧有关。光棘球海胆表现出五种颜色形态（粉色、棕色、绿色、灰色和黑色），这些颜色形态经常在同一块岩石上并排出现。我们研究了巴西海岸三个种群中这些形态之间的遗传分歧。分析了编码线粒体 ATP 合酶 8 和 6 个线粒体基因的区域、核组蛋白内含子的一个片段和编码精子蛋白结合蛋白的整个核基因的片段。线粒体 DNA 在粉色和所有其他形态之间存在差异，但组蛋白内含子在所有颜色形态中相似。在结合蛋白中，发现有 9 个密码子受到正选择，并且在颜色形态之间的几乎所有成对比较中都观察到等位基因频率的显著差异。虽然结合蛋白中的分子分化还不足以表明生殖隔离，但在该物种中，形态内的某种程度的交配选择似乎正在发生。
