The development of bovine syndactylism
1968; The Company of Biologists; Volume: 19; Issue: 2 Linguagem: Inglês
10.1242/dev.19.2.251
ISSN1477-9129
Autores Tópico(s)Plant Taxonomy and Phylogenetics
ResumoABSTRACT In homozygous condition, the gene for syndactylism (symbol sy) in Holstein-Friesian cattle has a variable manifestation. Affected limbs typically have a single digit with a single hoof. This happens more often on the fore than on the hind limbs, and some sy/sy animals show no syndactylism at all. Whereas normally the blastemata for digits III and IV at first diverge widely from each other, those of sy/sy embryos arise close to and approximately parallel to each other and have a tendency to coalesce distally. If coalescence is complete, a single but rather massive digit is formed; incomplete fusion may give rise to limbs with incomplete syndactylism, and if coalescence fails to happen the digits remain separate and have separate hooves. The limb buds of sy/sy embryos are thicker but correspondingly narrower from side to side, and it is probable (but not certain) that the atypical shape of the limb buds is the cause of the close juxtaposition in which the digital blastemata are laid down in the first instance.
Referência(s)