Genetic Variability in Exon 3 Region of POU1F1 Gene and its Effect on Body Weight and Milk Yield in Malabari Goats

Abstract

Background: POU1F1 is known as a major candidate gene coding for pituitary-specific transcription factor-1 regulating the production of anterior pituitary hormones like GH, TSH, LH, FSH and prolactin in small ruminants. However, little is known about the genetic variability of caprine POU1F1 gene in Indian breeds. Hence, the present study aimed at the identification of single nucleotide polymorphisms in the exon 3 region of POU1F1 and their association with body weight and milk production in Malabari goats. Methods: The present study was conducted during 2016-2018 on 100 Malabari goats at the University Goat and Sheep Farm, Mannuthy. Genomic DNA was extracted using standard phenol-chloroform method. The POU1F1 exon 3 locus was PCR amplified using appropriate primers. The 234 bp PCR product was subjected to single-strand conformation polymorphism (SSCP) analysis on 12% PAGE gel and silver-stained. The different SSCP patterns were sequenced and homologous sequences identified using Blast algorithms. Allelic-genotypic frequencies and the observed-expected heterozygosity at the locus were estimated. Data on body weights at birth, three, six, nine months of age and parity-wise lactation milk yield were used to find the association of POU1F1 exon 3 variants with body weights and milk yield using one-way ANOVA in General Linear Models for fixed effects. Result: PCR-SSCP revealed GG, GA genotypes with frequencies of 0.44 and 0.56 and G and A alleles with frequencies of 0.72 and 0.28. The observed and expected heterozygosity for the locus were 0.5657 and 0.4077 respectively. Sequencing of the PCR products revealed a synonymous single nucleotide polymorphism (g. 42C>T). GG homozygotes had higher body weight while GA heterozygotes had higher milk yield (p less than 0.05). It was concluded that the polymorphic exon 3 locus significantly contributed to variation in pre-pubertal body weight and milk yield and hence may be employed in the marker-assisted selection programmes for Malabari goats.