GENETIC DIVERSITY OF NIGERIAN INDIGENOUS GOAT BREEDS AT THE GROWTH HORMONE (GH) GENE LOCUS
Emmanuel Abayomi ROTIMI, Ojoh Michael MOMOH, Joseph Ochoche EGAHI
Abstract: In Nigeria, goats are important as potential source of meat, milk and skin production as well as
income. Improving the growth performance of these goat breeds can lead to increase meat, milk
and skin production. Growth hormone (GH) gene is associated with growth, bone formation, regulating
fat content and other important traits in goat. This study was conducted to assess the genetic
diversity of the three Nigerian indigenous goat breeds namely; Sahel (SAH), Sokoto Red (SOR) and
West African Dwarf (WAD). Fifteen animals were randomly sampled for this study. Five animals per
breed were selected and blood samples were collected into EDTA tubes, thereafter, genomic DNA
was extracted. A pair of primers was used to amplify GH gene region. Direct sequencing method
was applied for PCR products to study polymorphisms at the GH gene locus of the three Nigerian
goat breeds. The observed heterozygosity (Ho) ranged from 0.10 ± 0.10 (SAH) to 0.30 + 0.10 (WAD)
while the expected heterozygosity (He) ranged from 0.33 ± 0.01 to 0.44 ± 0.02. The overall Shannon
index (I), fixation index (F) and Polymorphic Information Content (PIC) values were 0.63 ± 0.04,
0.50 ± 0.12 and 0.49 ± 0.03 respectively. Gene flow (Nm) between WAD and SOR goats was 40.25,
WAD and SAH goats was 19.22 while between SOR and SAH was 37.25. The analysis of molecular
variance (AMOVA) within and between populations of goats that 100% of the observed variance
occurred within the breeds. The nearest genetic distance was observed between the SOR and SAH
breeds (0.0070) indicating closer geographical locations while the largest distance was between WAD
and SAH breeds (0.0124). The phylogenetic tree was drawn revealed that the SAH and SOR breeds
clustered together while the WAD breed diverged first, confirming the genetic distance results. The
present study showed that the distinctiveness of these indigenous goats is fast eroding, therefore effort
should be made to control the wearing away of the genetic make-up of the goat populations by adopting
improved breeding and management practices.
income. Improving the growth performance of these goat breeds can lead to increase meat, milk
and skin production. Growth hormone (GH) gene is associated with growth, bone formation, regulating
fat content and other important traits in goat. This study was conducted to assess the genetic
diversity of the three Nigerian indigenous goat breeds namely; Sahel (SAH), Sokoto Red (SOR) and
West African Dwarf (WAD). Fifteen animals were randomly sampled for this study. Five animals per
breed were selected and blood samples were collected into EDTA tubes, thereafter, genomic DNA
was extracted. A pair of primers was used to amplify GH gene region. Direct sequencing method
was applied for PCR products to study polymorphisms at the GH gene locus of the three Nigerian
goat breeds. The observed heterozygosity (Ho) ranged from 0.10 ± 0.10 (SAH) to 0.30 + 0.10 (WAD)
while the expected heterozygosity (He) ranged from 0.33 ± 0.01 to 0.44 ± 0.02. The overall Shannon
index (I), fixation index (F) and Polymorphic Information Content (PIC) values were 0.63 ± 0.04,
0.50 ± 0.12 and 0.49 ± 0.03 respectively. Gene flow (Nm) between WAD and SOR goats was 40.25,
WAD and SAH goats was 19.22 while between SOR and SAH was 37.25. The analysis of molecular
variance (AMOVA) within and between populations of goats that 100% of the observed variance
occurred within the breeds. The nearest genetic distance was observed between the SOR and SAH
breeds (0.0070) indicating closer geographical locations while the largest distance was between WAD
and SAH breeds (0.0124). The phylogenetic tree was drawn revealed that the SAH and SOR breeds
clustered together while the WAD breed diverged first, confirming the genetic distance results. The
present study showed that the distinctiveness of these indigenous goats is fast eroding, therefore effort
should be made to control the wearing away of the genetic make-up of the goat populations by adopting
improved breeding and management practices.
Keywords: direct sequencing; Goat breeds; growth hormone; indigenous
Date published: 2021-02-26
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