PolydactylismIn Muscovy Ducks (Cairina moschata): Inheritance And Types Of Polydactyly

Abstract

Polydactyly is one of the most co mmon congenital limb dysplasia frequently observed in fa rm anima ls and varies in e xpressivity. He rein, a preliminary investigation on inheritance and types of polydactylyin one hundred and four (104) ducklings produced by seven (7) mating g roups (MGs) of different genotypes werereported. These ducklings were produced from non descript random bred population of Muscovy ducks in the Netherlands and data generated were ana lysed with descriptive (percentage and bar chart) and infe rential statistics{Chi-square (χ2)}. The resultsindicated that irrespective of the genotypes of the parents, polydactyl gene (Po) had inco mplete do minance and penetrance in the ducklings; however, the observed frequencies of polydactyly was not significantly (P>0.05) d ifferent fro m the e xpected proportions in all M Gs. Fu rther analysis of expressivity of the gene revealed prevalence of bilateral e xpression (97.18% ) co mpared to the unilatera l inc idence (2.82% ).The phenotypic e xpression of the mutant gene was classified into sixteen (16) distinct types and about one-third (31.82%) of polydactyl ducklings exp ressed type 5 polydactyly. In addition, dosage effect of Poand twin polyphalangeal(PoTP) genes exerted influence on incidence of polydactylism and observed polydactyly types. The highest number of polydactyly type was e xpressed by progenies of homozygous polydactyl parents. Conversely, PoTPgene was antagonistic to the expression of polydactylyand the incidence of polydactylysim was highest among ducklings of non-twin polyphalangeal parents.