33 Present address: 1 Scientist (drrajnikumari@rediffmail.com), 2,5 Senior Scientist (antudayal@gmail.com, asit1963 @yahoo.com), 6 Chief Technical Officer (skbarari@yahoo.co.in), 7 Principal Scientist and Head (amitavdey_icar@yahoo.co.in), Division of Livestock and Fishery Management. 3 Assistant Professor-cum-Junior Scientist (sanjayvet29 @rediffmail.com), Department of Animal Nutrition, Bihar Veterinary College, Patna. 4 SMS (shardullal84@gmail.com), Animal Science, Nimbudera, ICAR-CIARI, Port Blair. Prolificacy, the ability of a female animal to produce large number of young ones in their life span through high ovulation rate and high embryo survival, is affected by many genes in small ruminants. These include bone morphogenetic protein receptor type–1 gene (BMPR1B), growth differentiation factor -9 (GDF9), bone morphogenetic factor (BMP15) gene, estrogen receptor gene, Kisspeptin gene and others. Candidate gene approach of these prolificacy genes provides an alternate tool for early breeding that can accelerate the improvement of goat (Zhang et al. 2009). Inheritance of twinning and triplet is similar in both sheep and goats (Hua et al. 2008). These genes have been extensively studied in sheep unlike goat. Studies on relationship between ovulation rate and litter size reported that a set of genes were regulating this complex phenomenon known as fecundity (Fec) genes (Davis et al.1982, Baird et al.1998). These belong to the transforming growth factor beta (TGF-ß) super family. Limited studies have been attempted on prolificacy of goats. Therefore, the genetic basis of caprine prolificacy needs to be explored. Indian goat breed, Black Bengal, is an important breed Indian Journal of Animal Sciences 85 (5): 469–471, May 2015/Article Genetic polymorphism of bone morphogenetic protein receptor type–1 gene in Black Bengal goat and its association with litter size RAJNI KUMARI 1 , SHANKER DAYAL 2 , SANJAY KUMAR 3 , S V LAL 4 , ASIT CHAKRABORTI 5 , S K BARARI 6 and AMITAVA DEY 7 ICAR Research Complex for Eastern Region, Patna, Bihar 800 014 India Received: 17 October 2014; Accepted: 6 January 2015 ABSTRACT The genetic polymorphism of the bone morphogenetic protein receptor type–1 gene (BMPR1B) was studied in 100 does of Black Bengal goats. The study revealed 2 genetic variants, A (0.25) and G (0.75) and 2 genotypes, AG (0.5) and GG (0.5). Genotypic and allelic frequencies at BMPR1B locus revealed the abundance of mutant type (G) nucleotide in Black Bengal goats. All animals, were found to carry the mutant allele. A positive correlation was observed between the litter size and mutant type genotype. Heterozygous carrier and homozygous carrier does had litter size of 1.6± 0.26 and 2.07 ±0.28 respectively. The results showed that BMPR1 B polymorphism may be targeted for upgrading low prolific breeds of Indian goat by introgression of this mutation in non prolific breeds by crossing. Key words: Association, Black Bengal goat, BMPR1B gene, Litter size for mutton production and most prolific. Twinning is more frequent (56.32%) and quadruplet is least frequent (2.11%) (Hassan et al. 2007). It shares the breeding tract of Garrole sheep, which has been extensively studied for prolificacy. Bihar contributes about 7.63% of India’s total goat population. Village goat is mostly of Bengal breed. However, crosses with other breeds like Jamunapari, Barbari, Sirohi and Jakharana are also available. This breed is highly prolific and twining percentage has been recorded as 45 (De et al. 2007). There is an urgent need to investigate the genes linked to prolificay, which could enable us to formulate the breeding strategies to introduce the prolificacy into local breeds and further genetic improvement. Polley et al. (2009) studied major genes responsible for prolificacy in Black Bengal from West Bengal and found BMPR 1B also known as fecundity b (Fec B) gene as polymorphic. The present study is in continuation of study by Polley et al. (2009) and aims at further studying the polymorphism of BMPR1B gene in Black Bengal goats from Bihar in India and to investigate its linkage with increased prolificacy. MATERIALS AND METHODS Experimental flock and sampling: Blood samples of 100 Black Bengal does were randomly collected from does maintained at institute farm and different villages of Bihar. Approximately 5 ml blood sample was collected from jugular vein in EDTA tube and was transferred to –20°C freezer. The history of litter size in respective kidding for every doe was collected from the farmers. DNA isolation: DNA was extracted from white blood