Carmona J A, Sanjur O I, Doadrio I, Machordom A, Vrijenhoek R C
Museo Nacional de Ciencias Naturales, José Gutiérrez Abascal, Madrid, Spain.
Genetics. 1997 Jul;146(3):983-93. doi: 10.1093/genetics/146.3.983.
Iberian minnows collectively known as the Tropidophoxinellus alburnoides Steindachner complex comprise diploid and polyploid forms with highly female biased sex ratios. Previous investigators suggested that all-female clonal reproduction and interspecific hybridization may occur in this complex. We examined nuclear (allozymes) and cytoplasmic genes (mtDNA) to assess the evolutionary origins, relationships, and reproductive modes of T. alburnoides from western Spain. The multi-locus allozyme data clearly revealed the hybrid nature of all polyploid forms of this fish and some diploid forms as well. Diagnostic markers identified fish from the genus Leuciscus as the paternal ancestor of hybrids in the Duero and Guadiana River Basins. Additionally, analysis of nuclear markers revealed that hybridogenetic reproduction occurs in the diploid and triploid hybrids. The hybrids fully express the paternal Leuciscus genome and then discard it during oogenesis. Hybridogenetic ova contain only maternal nuclear genes and mtDNA from a non-hybrid T. alburnoides ancestor. Apparently diploid and triploid hybrids of T. alburnoides persist as sperm parasites on males of a sexually reproducing Leuciscus host species.
伊比利亚米诺鱼统称为阿尔氏细脂鲤复合体（Tropidophoxinellus alburnoides Steindachner complex），包含二倍体和多倍体形式，且性别比例高度偏向雌性。先前的研究人员认为，全雌性克隆繁殖和种间杂交可能在该复合体中发生。我们检测了核基因（同工酶）和细胞质基因（线粒体DNA），以评估西班牙西部阿尔氏细脂鲤的进化起源、亲缘关系和繁殖模式。多位点同工酶数据清楚地揭示了这种鱼所有多倍体形式以及一些二倍体形式的杂交本质。诊断标记将雅罗鱼属（Leuciscus）的鱼类鉴定为杜罗河和瓜迪亚纳河流域杂种的父本祖先。此外，对核标记的分析表明，二倍体和三倍体杂种中存在杂交起源生殖。杂种完全表达父本雅罗鱼的基因组，然后在卵子发生过程中将其丢弃。杂交起源的卵子仅包含母本核基因和来自非杂交阿尔氏细脂鲤祖先的线粒体DNA。显然，阿尔氏细脂鲤的二倍体和三倍体杂种作为精子寄生物寄生于有性繁殖的雅罗鱼属宿主物种的雄鱼身上。
