Langhorst L J, Fechheimer N S
J Hered. 1985 May-Jun;76(3):182-6. doi: 10.1093/oxfordjournals.jhered.a110061.
A mutant condition characterized by absence of shanks is invariably present in chickens that are homokaryotypic for an X-ray-induced pericentric inversion to chromosome 2. The mutation was studied in 260 embryos at 19 days of incubation. Embryos produced from matings of parents with and without the inversion were karyotyped and their skeletons observed and measured. The mutant phenotype, which was seen in all birds homokaryotypic for the inversion, is characterized by malformed and reduced metacarpals, absence of tarsometatarsal shanks, increased tibia length, extra bones in digits two, three, and four, and fusion of proximal phalanges. Heterokaryotypic and homokaryotypic normal embryos had normal phenotypes, but the length of metacarpals was slightly reduced in heterokaryotypes. The primary effect of the mutation is to cause misplacement, malformation, and underdevelopment of metatarsals II, III, and IV. The recessive mutation, located in the proximal region of chromosome 2, has been designated shankless (shl).
一种以无胫部为特征的突变状况总是出现在因X射线诱导的2号染色体臂间倒位而呈同核型的鸡中。在孵化19天的260个胚胎中对该突变进行了研究。对有和没有这种倒位的亲本交配产生的胚胎进行了核型分析，并观察和测量了它们的骨骼。在所有因倒位而呈同核型的鸟类中都出现的突变表型，其特征为掌骨畸形且缩短、跗跖骨胫部缺失、胫骨长度增加、第二、第三和第四趾中有额外的骨头以及近端指骨融合。异核型和同核型正常胚胎具有正常表型，但异核型中掌骨长度略有缩短。该突变的主要影响是导致第二、第三和第四跖骨错位、畸形和发育不全。位于2号染色体近端区域的隐性突变已被命名为无胫（shl）。
