Journal of Animal Breeding and Genomics (J Anim Breed Genom)
Hassan-Okoh, Abdulhakeem Temitope1,2 and Toye, Ayokunle Afolabi2
1Nigeria Agricultural Quarantine Service, Post-Entry Diagnostic Station, Moor Plantation, Ibadan, Nigeria.
2Quantitative, Molecular and Functional Genetics Group, Department of Animal Production, Faculty of Agriculture, University of Ilorin, Ilorin, Nigeria.
Correspondence to Ayokunle Afolabi Toye, E-mail: ayo.a.toye@gmail.com
Volume 3, Number 2, Pages 45-58, June 2019.
Journal of Animal Breeding and Genomics 2019, 3(2), 45-58. https://doi.org/10.12972/jabng.20190006
Published on June 30, 2019.
Copyright © 2019 Korean Society of Animal Breeding and Genetics.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0).
Somatotropic Axis Genes are candidate genes for differential growth determination. Component exons (and 50 bases immediately 5’ and 3’ of each exon) of IGF1 (4 Exons) and cGH (5 Exons), were amplified from DNA of fast (Hubbard Broiler, HB), and slow (Nigerian Local Chickens: Fulani Ecotype, FE and Yoruba Ecotype, YE) growing chickens. Sequenced and aligned against each other and against Genbank published orthologs spanning Aves, Mammals, Pisces and other vertebrates. Phylograms were constructed from aligned sequences. Regulatory motifs within noncoding DNA sequence were identified. Of the exons examined, all but exon 5 of cGH were successfully amplified in all breeds. However, only 33% of IGF1 (HB, exon 2 and 3; FE exon 3; YE exon 2) and 42% of cGH (HB, exon 2 and 3; FE exon 1 and 3; YE exon 1) exons were successfully sequenced. No inter-breed (between HB, YF, and FE) coding sequence polymorphisms were detected. Equally, none was detected in comparisons with published Jungle Fowl sequence (RJF; ENSGALT00000000328 and ENSGALT00000020816, Ensembl.org). Four polymorphisms were detected in the 5’ and 3’ flanking DNA of sequenced exons, including: a cGH 1644 A>G (RJF > HB, FE) single nucleotide polymorphism or SNP; a cGH 1850 G>A (RJF > FE) SNP; a cGH 1860 T>C (RJF >FE) SNP and; an IGF1 4662 – 4673insT insertion polymorphism. Three of these polymorphisms overlapped regulatory motifs. The lack of polymorphisms in aligned sequences suggests these particular Exons are not responsible for the differences in growth rate observed between the breeds.
Gene, Polymorphism, Chickens, Exon, Intron.
Further studies to search for other mutations to characterise the unsuccessful part of this present study is recommended. Furthermore, other candidate genes that have also been associated with growth in other breeds of chickens should be amplified and sequenced in NLC in a bid to creating a prerequisite for their improvement. The regulatory sequences revealed in the present study should be research upon to determine their influence on the genes observed; as this transcriptional binding sites might be pertinent to the final genes transcripts in the respective breeds.