ABSTRACT

The cannonball jellyfish Stomolophus meleagris display colour variations from blue to purple, and different pigmentation patterns on the umbrella surface. Although these colour phenotypes are common in this organism, surprisingly, little is known about the causes and the adaptive significance of these polymorphisms. In this study, we investigated the population genetic structure of S. meleagris distributed in the Gulf of California based on the partial regions of mitochondrial COI and 12S rRNA genes. Sample collections were carried out, and morphological data from organisms, as well as physicochemical parameters of the seawater at the collection sites, were recorded. White and blue phenotypes were found in April, and blue specimens were the more abundant. No specimens of the white phenotype were found in May, and the purple phenotype was present only in June. A correlation was found between the occurrences of white jellyfish and lower seawater temperatures (23.5 °C). Ten different COI gene haplotypes were detected, and 20 12S rRNA gene haplotypes. The clustering of haplotypes was not correlated with their geographical distributions. Moderate and low values of F_ST were obtained between samples collected in different locations. These results suggest that S. meleagris in the Gulf of California exist as a single genetic stock, and the different pigmentation patterns observed may result from specific environmental conditions.

摘要

炮弹水母Stomolophus meleagris显示出从蓝色到紫色的颜色变化，并且伞表面的色素沉着模式也不同。尽管这些颜色表型在该生物中很常见，但令人惊讶的是，对于这些多态性的原因和适应性意义知之甚少。在这项研究中，我们调查了S. meleagris的种群遗传结构。根据线粒体COI和12S rRNA基因的部分区域分布在加利福尼亚湾。进行了样品收集，并记录了来自生物体的形态数据以及收集地点海水的理化参数。在4月发现了白色和蓝色的表型，蓝色标本则更为丰富。在五月份没有发现白色表型的标本，只有在六月才出现紫色表型。发现白水母的发生与海水温度较低（23.5°C）之间存在相关性。检测到十种不同的COI基因单倍型，以及20种12S rRNA基因单倍型。单倍型的聚类与其地理分布无关。F _ST的中低值是在不同位置收集的样本之间获得的。这些结果表明，在加利福尼亚湾的S. meleagris是作为单一遗传种群存在的，观察到的不同色素沉着模式可能是由特定的环境条件引起的。