Karl S A, Bowen B W, Avise J C
Department of Biology, University of South Florida, Tampa 33620-5150, USA.
J Hered. 1995 Jul-Aug;86(4):262-8. doi: 10.1093/oxfordjournals.jhered.a111579.
Reports of hybridization between marine turtle species (family Cheloniidae) have been difficult to authenticate based solely on morphological evidence. Here we employ molecular genetic assays to document the sporadic, natural occurrence of viable interspecific hybrids between species representing four of the five genera of cheloniid sea turtles. Using multiple DNA markers from single-copy nuclear loci, eight suspected hybrids (based on morphology) were confirmed to be the products of matings involving the loggerhead turtle (Caretta caretta) x Kemp's ridley (Lepidochelys kempii) (N = 1 specimen), loggerhead turtle x hawksbill (Eretmochelys imbricata) (N = 2), loggerhead turtle x green turtle (Chelonia mydas) (N = 4), and green turtle x hawksbill (N = 1). Molecular markers from mitochondrial DNA permitted identification of the maternal parental species in each cross. The species involved in these hybridization events represent evolutionary lineages thought to have separated 10-75 million years ago (mya) and thus may be among the oldest vertebrate lineages capable of producing viable hybrids in nature. In some cases, human intervention with the life cycles of marine turtles (e.g., through habitat alteration, captive rearing, or attempts to establish new breeding sites) may have increased the opportunities for interspecific hybridization.
仅基于形态学证据，很难证实海龟物种（蠵龟科）之间存在杂交现象。在此，我们采用分子遗传学分析方法，记录了蠵龟科海龟五个属中四个属的物种间偶尔自然出现的可存活种间杂交情况。利用来自单拷贝核基因座的多个DNA标记，确认了八只疑似杂交种（基于形态学判断）是由蠵龟（Caretta caretta）与肯氏龟（Lepidochelys kempii）杂交产生的后代（1个样本）、蠵龟与玳瑁（Eretmochelys imbricata）杂交产生的后代（2个样本）、蠵龟与绿蠵龟（Chelonia mydas）杂交产生的后代（4个样本）以及绿蠵龟与玳瑁杂交产生的后代（1个样本）。线粒体DNA的分子标记能够确定每个杂交组合中的母本物种。参与这些杂交事件的物种代表了被认为在1000万至7500万年前就已分化的进化谱系，因此它们可能是自然界中能够产生可存活杂交后代的最古老脊椎动物谱系之一。在某些情况下，人类对海龟生命周期的干预（例如，通过改变栖息地、圈养繁殖或尝试建立新的繁殖地点）可能增加了种间杂交的机会。
