Inbreeding trends and genetic diversity in purebred sheep populations

Rafter, Pierce; McHugh, N.; Pabiou, T.; Berry, D.P.

doi:10.1016/j.animal.2022.100604

Cited by 17 publications

(15 citation statements)

References 32 publications

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“…The significant interactions observed between subject effects, specifically strain × genotype and mating system × genotype ( P < 0.0001), and suggest that birth weight in lambs is influenced by complex genetic and mating factors. The lower birth weight in homozygous variant genotypes could be attributed to the historical in-breeding and outcrossing practices, indicating that genetic diversity plays a crucial role in determining birth weight outcomes [ 52 , 53 ]. These findings highlight the importance of managing genetic diversity in breeding programs to improve lamb birth weight outcomes.…”

Section: Resultsmentioning

confidence: 99%

Assessing the performance of Moghani crossbred lambs derived from different mating systems with Texel and Booroola sheep

Talebi,

Mardi,

Zeinalabedini

et al. 2024

PLoS ONE

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In our ongoing project, which focuses on the introgression of Booroola/FecB gene and the myostatin (MSTN) gene into purebred Moghani sheep, we assessed the performance of second-generation Moghani crossbreds such as second crossbreds (F2) and initial backcross generation (BC1). These crossbreds were generated through different mating systems, including in-breeding, outcrossing, first paternal backcrossing (PBC1), and first maternal backcrossing (MBC1). Notably, F2 strains exhibited lean tail, woolly fleece and a higher percentage of white coat color compared to BC1. The impact of mating systems and birth types on pre-weaning survival rates was found to be statistically significant (P < 0.0001), with singleton offspring resulting from paternal backcross showing a particularly substantial effect. The F2 crossbred lambs carrying the Booroola gene did not show a statistically significant difference in survivability compared to those carrying the MSTN gene, implying the Booroola prolificacy gene had no significant impact on survival outcomes. However, the occurrence of multiple births had a significant negative impact on lamb survival (P < 0.0001). The PBC1 sheep strains, specifically Texel Tamlet ram strains carrying the MSTN mutation, exhibited superior growth rates compared to others (P < 0.05). Interestingly, the MSTN mutation in the homozygous variant genotype significantly impacts growth rate before weaning compared to other genotypes and pure Moghani sheep (P < 0.05). In conclusion, this study objectively underscores the pivotal role of genetic factors, specifically through strategic mating systems like paternal backcrossing, in enhancing desired traits and growth rates in Moghani sheep, thereby contributing valuable insights to the field of sheep breeding programs.

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Section: Resultsmentioning

confidence: 99%

Assessing the performance of Moghani crossbred lambs derived from different mating systems with Texel and Booroola sheep

Talebi,

Mardi,

Zeinalabedini

et al. 2024

PLoS ONE

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“…Higher genetic diversity was observed for numerous SFK and DRP breeds, whereas GME and ROM breeds were relatively less diverse than LDS. The CHR sheep had the highest diversity estimates, including effective population size and the effective number of founders, among breeds such as SFK, TEX, and the less numerous Galway sheep, according to pedigree records of more than 120′000 purebred animals [ 44 ]. Yet another study aimed at pedigree data analysis among German sheep populations listed CHR sheep as less diverse than SFK, indicating that the population of origin might influence conclusions drawn from comparing different breeds [ 45 ].…”

Section: Discussionmentioning

confidence: 99%

“…The DRP sheep, as a composite breed, has been previously reported to harbor high genetic diversity [ 47 ]. According to in-depth pedigree analysis, internationally widely distributed sheep belonging to the SFK breed are considered genetically diverse [ 44 , 45 , 48 ]. However, genomic estimates indicate that individual populations may have lost at least a small proportion of the original genetic diversity [ 35 , 39 ].…”

Section: Discussionmentioning

confidence: 99%

Genomic diversity of the locally developed Latvian Darkheaded sheep breed

Gudra,

Valdovska,

Kairisa

et al. 2024

Heliyon

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“…Nonetheless, although both siblings have the same parents, estimated genomic inbreeding coefficients differ between full-siblings, which is an outcome of independent assortment of haplotypes to sister chromatids during gamete formation. The results of this analysis have important implications for breeding and management strategies for cattle and sheep where inbreeding can be incidental due to the low effective population sizes of cattle and sheep [ 17 , 18 ]. This can also be the case for species such as chickens and pigs, where it is common to perform intense selection within purebred lines of animals for the purposes of outcrossing [ 19 , 20 ].…”

Section: Discussionmentioning

confidence: 99%

Variation in the proportion of the segregating genome shared between full-sibling cattle and sheep

et al. 2023

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The construction of covariance matrices that account for the genetic relationships among individuals, using pedigree or genotype data, is integral to genetic evaluations, which are now routinely used in the field of animal breeding. The objective of the present study was to estimate the standard deviation in the proportion of the segregating genome that is shared between pairs of full-sibling cattle and sheep independently. Post edits, genotype data comprising 46,069 autosomal single nucleotide polymorphisms (SNPs) were available for 4532 unique full-sibling sheep pairs, as well as for their respective parents. Post edits, genotypes from 50,493 autosomal SNPs were also available for 10,000 unique full-sibling cattle pairs, as well as their respective parents. Genomic relationship matrices were constructed for the sheep and cattle populations, separately. After accounting for both parental genomic inbreeding and the genomic relationship between both parents, the standard deviation in full-sibling cattle and sheep genomic relationships was 0.040 and 0.037 units, respectively. In addition, the intercept value from a linear regression model which regressed each full-sibling genomic relationship on both sire and dam inbreeding, as well as the genomic relationship between the parents, was 0.499 (0.001) for sheep and 0.500 (0.001) for cattle, conforming to the expectation that full-siblings, on average, share 50% of their segregating genome.

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Inbreeding trends and genetic diversity in purebred sheep populations

Cited by 17 publications

References 32 publications

Assessing the performance of Moghani crossbred lambs derived from different mating systems with Texel and Booroola sheep

Assessing the performance of Moghani crossbred lambs derived from different mating systems with Texel and Booroola sheep

Genomic diversity of the locally developed Latvian Darkheaded sheep breed

Variation in the proportion of the segregating genome shared between full-sibling cattle and sheep

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