PRESENCE OF THE POLYDACTYLY GENJ EFJTHE NIGERHAM LOCAL CHICKEN

Abstract

An investiga%ionw as carried out to determine the percent incidence of the polydactylous  condition and the frequencies of the genes, Po and po, in this condition in the mature Nigerian local chicken reared in south-western Nigeria, A total of 2018 adult local chickens of both sexes managed under the predominant scavenging system were surveyed and only nine were polydactylous. The penetrance of the polydactylous condition was generally low (0.446 %) in south-western Nigeria, giving rise to a frequency 0.002 for the dominant allele, Po, inluensing the condition, Frequency of the recessive allele, po, was 0.998 and these values were signifiearltly different from expected values, This could possibly be due to the role of natural selection and social preference among the papujace operating against birds manifesting the character. Thc average length of the extra digit was 2-17 cm and was Ionger in males (2.50 cm) than in females (1.90cm). The effect of $he incidence of the condition was significantt ( P< 0.05) for only wing length and breast girth, favourng mature birth with the 'normal' four toes. Wing lengths averaged 16.25 cm and 13.88 cm for the non-dactylous birds and the polydactylous birds respectively, while breadt circumference averaged 27.25 cm and 25.55 cm for the two groups respectively. These values differed significantly from one another and they provide further justification for the apparent social preference against polydactylous local chickens of south-western Nigeria.