Genetic Characterization of Insulin Growth Factor-1 and Its Receptor Genes in Egyptian Buffalo (Bubalus bubalis L.)

Aim: The somatotropic axis (SA) comprises genes associated with economically important quantitative traits in livestock like mammary and muscle growth as well as carcass traits. Insulin growth factor-1 (IGF-1) and its receptor (IGF-1R) are two important genes belonging to the SA. The aim of this study was to evaluate the genetic polymorphism of IGF1/SnaBI and IGF-1R/TaqI restriction sites in Egyptian buffalo.

Methodology: Genomic DNA was extracted from blood samples of 100 healthy buffaloes maintained at the Mahlet Mussa and El-Gmeasa herds from 2010 to 2012. PCR was performed using primers flanking a 250-bp fragment of the regulatory region of the buffalo IGF-1 gene and a 616-bp fragment of the IGF-1R gene encompassing 51-bp from exon 12, 479-bp from intron 12 and 86-bp from exon 13. The PCR-amplified fragments were digested with SnaBI (IGF-1) and TaqI (IGF-1R), electrophoresed and analyzed on agarose gels stained with ethidium bromide. The two amplified fragments were also sequenced and aligned with published sequences.

Results: All buffaloes investigated in this study were genotyped BB (i.e., negative for the SnaBI restriction site at position 224^225 (TAC^GTA) of the IGF-1 regulatory region) and AA (i.e., positive for the TaqI restriction site at position 47^48 (T^CGA) of the IGF-1R exon 12).

Conclusion: Our Egyptian buffaloes were homozygous BB and AA for IGF1/SnaBI and IGF-1R/TaqI restriction sites, respectively. The nucleotide sequence data were submitted to NCBI/Bankit/GenBank with the accession numbers KC852883 and KC852884 for Egyptian buffalo IGF-1 and IGF-1R genes, respectively. The study of variation in these sequences may be useful in future marker-assisted selection (MAS) and genetic conservation programs.