Association of growth performance and body conformational traits with BMP4 gene variation in Barki lambs

Genetic structure of some candidate genes of repeat breeder syndrome in Egyptian buffaloes

Background

This study aimed to explore the association between polymorphisms in three genes: leptin (LEP), leptin receptor (LEPR), and BMP4, and incidence of repeat breeding in Egyptian buffaloes.

Methods

DNA was extracted from 160 female buffaloes, involving 108 fertile and 52 repeat breeders. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Sequence analysis and alignment were performed by employing NCBI/BLAST/blastn suite, to identify SNPs among different patterns and alleles. We utilized PredictSNP software to predict the non-synonymous SNPs influences on protein function. Moreover, the conservation score of the amino acids within the target proteins was computed by ConSurf server.

Results

The genotyping results showed that LEP and BMP4 genes were monomorphic (CC, GG) in all tested fertile and repeat breeder buffaloes. Leptin gene sequencing showed a non-synonymous C73T SNP, replacing R to C at position 25 within the leptin polypeptide (position 4 in the mature form; R4C) which is a neutral mutation, not affecting function or structure of LEP protein. For LEPR, one synonymous SNP (T102C) and two non-synonymous SNPs (A106G and C146A), triggering V967A and G954C replacements, respectively in LEPR protein. Moreover, they are neutral mutations. Sequencing results of BMP4 showed HinfI restriction site indicate fixed GG genotype (CC genotype in the anti-sense strand) in all sequenced samples. No SNPs were observed within the amplified region.

Conclusion

Genotyping and sequencing results of the surveyed three genes revealed that there is no association between these genes mutations and the incidence of repeat breeding in Egyptian buffaloes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43141-022-00397-2.

Polymorphisms in hormone-sensitive lipase and leptin receptor genes and their association with growth traits in Barki lambs

Background and Aim

Marker-assisted selection has many advantages over conventional selection in animal breeding. The candidate gene approach has been applied to identify genetic markers associated with economically important traits in livestock. This study was established to investigate variation in the hormone-sensitive lipase (HSL) and leptin receptor (LEPR) genes, and their association with growth traits in Barki lambs.

Materials and Methods

Records for birth weight (BW), pre-weaning average daily gain (ADG1), weaning weight (WW), post-weaning average daily gain (ADG2), and marketing weight (MW) were obtained from 247 Barki lambs. Polymerase chain reaction-single-stranded conformational polymorphism analyses were used to detect variation in exon 9 of HSL and exon 19 of LEPR. General linear models were used to test for associations between the variation in ovine HSL and LEPR, and growth traits.

Results

The SSCP banding patterns for HSL showed three variants (H1, H2, and H3), which contained two nucleotide-sequence differences (c.1865C>T and c.2038T>C). Two SSCP banding patterns (L1 and L2) were observed for LEPR and these contained two nucleotide-sequence differences (c.2800G>A and c.2978C>G). The HSL genotype showed no effect on the studied traits. The LEPR genotype was proven to have significant effects (p<0.05) on ADG2 and MW. The presence of the L1 variant was associated (p<0.01) with decreased ADG2 and MW.

Conclusion

The finding of an association between LEPR gene variation and growth rate after weaning in Barki lambs warrants efforts to improve this trait.

Genetic variations in the Myostatin gene affecting growth traits in sheep

Background and Aim

Sheep productivity in developing countries is crucial, as this animal is an essential source of meat and wool. Myostatin (MSTN) plays an important role in the regulation of muscle mass through the regulation of muscle growth, differentiation, and regeneration. The present study sought to investigate genetic variation in the first intron of the MSTN gene and the association of variants with growth traits in major sheep breeds in Egypt (Barki, Ossimi, and Rahmani) and Saudi Arabia (Najdi) using polymerase chain reaction (PCR) and sequencing.

Materials and Methods

Blood samples were collected, and DNA was extracted from 75 animals. A 386 bp fragment in the first intron of the MSTN gene was amplified using PCR. Polymorphic sites were detected using direct sequencing and then correlated with growth traits using a general linear model.

Results

Sequence analysis of the first intron of MSTN gene identified six single-nucleotide polymorphisms (SNPs) in the studied breeds. Four mutual SNPs were determined: c.18 G>T, c.241 T>C, c.243 G>A, and c.259 G>T. In addition, two SNPs c.159 A>T and c.173 T>G were monomorphic (AA and TT, respectively) in the Ossimi, Rahmani, and Najdi breeds and polymorphic in the Barki breed. The association analysis revealed that the c.18 G>T and c.241 C>T significantly associated (p<0.05) with birth weight and average daily weight gain, respectively.

Conclusion

Our results strongly support MSTN as a candidate gene for marker-assisted selection in sheep breeding programs. Furthermore, the identified variants may be considered as putative markers to improve growth traits in sheep.

A missense mutation in the coding region of the toll-like receptor 4 gene affects milk traits in Barki sheep

OBJECTIVE

Milk production is one of the most desirable traits in livestock. Recently, the toll-like receptor (TLR) has been identified as a candidate gene for milk traits in cows. So far, there is no information concerning the contribution of this gene in milk traits in sheep. This study was designed to investigate the TLR 4 gene polymorphisms in Barki ewes in Egypt and then correlate that with milk traits in order to identify potential single nucleotide polymorphisms (SNPs) for these traits in sheep.

METHODS

A part of the ovine TLR 4 gene was amplified in Barki ewes, to identify the SNPs. Consequently; Barki ewes were genotyped using polymerase chain reaction-single strand conformation polymorphism protocol. These genotypes were correlated with milk traits, which were the daily milk yield (DMY), protein percentage (PP), fat percentage (FP), lactose percentage, and total solid percentage (TSP).

RESULTS

Age and parity of the ewe had a significant effect (p<0.05 or p<0.01) on DMY, FP, and TSP. The direct sequencing identified a missense mutation located in the coding sequence of the gene (rs592076818; c.1710C>A) and was predicted to change the amino acid sequence of the resulted protein (p.Asn570Lys). The association analyses suggested a significant effect (p<0.05) of the TLR genotype on the FP and PP, while the DMY tended to be influenced as well (p = 0.07). Interestingly, the presence of the G allele tended to increase the DMY (+40.5 g/d) and significantly (p<0.05 or p<0.01) decreased the FP (-1.11%), PP (-1.21%), and TSP (-7.98%).

CONCLUSION

The results of this study suggested the toll-like receptor 4 (TLR4) as a candidate gene to improve milk traits in sheep worldwide, which will enhance the ability to understand the genetic architecture of genes underlying SNPs that affect such traits.