Castillo A G F, Beall E, Moran P, Martinez J L, Ayllon F, Garcia-Vazquez E
Departamento Biologia Funcional, Universidad de Oviedo, 33006 Oviedo, Spain.
Mol Ecol. 2007 Apr;16(8):1741-8. doi: 10.1111/j.1365-294X.2007.03257.x.
Hybridization between sympatric species is not uncommon in the wild. Wild allotriploids (individuals with two chromosome sets from a species + one chromosome set from another species) are generally the result of a backcross between interspecific hybrids that produce unreduced gametes and one of the parental species. In animals, allotriploids are commonly sterile, except for some vertebrate species complexes in which allotriploids reproduce by parthenogenesis, gynogenesis and/or hybridogenesis, producing generally clonal or hemiclonal gametes; nuclear DNA introgression between hybridizing species is considered to be extremely rare. Employing species-specific molecular markers, we show genetic introgression between the chromosomally well-differentiated salmonids Atlantic salmon (2n = 58) and brown trout (2n = 80) through spontaneous bisexual reproduction of allotriploids leading to salmon-like offspring bearing some brown trout genes. Although introgression between these Salmo species can occur via allotriploids, we hypothesize that extinction of parental species can be discarded based on very low survival of allotriploid offspring.
在野外，同域物种之间的杂交并不罕见。野生异源三倍体（具有来自一个物种的两套染色体 + 来自另一个物种的一套染色体的个体）通常是产生未减数配子的种间杂种与亲本物种之一回交的结果。在动物中，异源三倍体通常是不育的，除了一些脊椎动物物种复合体，其中异源三倍体通过孤雌生殖、雌核发育和/或杂交生殖进行繁殖，通常产生克隆或半克隆配子；杂交物种之间的核DNA渗入被认为极其罕见。利用物种特异性分子标记，我们通过异源三倍体的自发双性繁殖展示了染色体差异明显的鲑科鱼类大西洋鲑（2n = 58）和褐鳟（2n = 80）之间的基因渗入，这种繁殖产生了携带一些褐鳟基因的类似鲑鱼的后代。虽然这些鲑属物种之间的基因渗入可以通过异源三倍体发生，但我们推测基于异源三倍体后代的极低存活率，可以排除亲本物种灭绝的可能性。
