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Nishio M, Inoue K, Ogawa S, Ichinoseki K, Arakawa A, Fukuzawa Y, Okamura T, Kobayashi E, Taniguchi M, Oe M, Ishii K. Comparing pedigree and genomic inbreeding coefficients, and inbreeding depression of reproductive traits in Japanese Black cattle. BMC Genomics 2023; 24:376. [PMID: 37403068 DOI: 10.1186/s12864-023-09480-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/23/2023] [Indexed: 07/06/2023] Open
Abstract
BACKGROUND Pedigree-based inbreeding coefficients have been generally included in statistical models for genetic evaluation of Japanese Black cattle. The use of genomic data is expected to provide precise assessment of inbreeding level and depression. Recently, many measures have been used for genome-based inbreeding coefficients; however, with no consensus on which is the most appropriate. Therefore, we compared the pedigree- ([Formula: see text]) and multiple genome-based inbreeding coefficients, which were calculated from the genomic relationship matrix with observed allele frequencies ([Formula: see text]), correlation between uniting gametes ([Formula: see text]), the observed vs expected number of homozygous genotypes ([Formula: see text]), runs of homozygosity (ROH) segments ([Formula: see text]) and heterozygosity by descent segments ([Formula: see text]). We quantified inbreeding depression from estimating regression coefficients of inbreeding coefficients on three reproductive traits: age at first calving (AFC), calving difficulty (CD) and gestation length (GL) in Japanese Black cattle. RESULTS The highest correlations with [Formula: see text] were for [Formula: see text] (0.86) and [Formula: see text] (0.85) whereas [Formula: see text] and [Formula: see text] provided weak correlations with [Formula: see text], with range 0.33-0.55. Except for [Formula: see text] and [Formula: see text], there were strong correlations among genome-based inbreeding coefficients ([Formula: see text] 0.94). The estimates of regression coefficients of inbreeding depression for [Formula: see text] was 2.1 for AFC, 0.63 for CD and -1.21 for GL, respectively, but [Formula: see text] had no significant effects on all traits. Genome-based inbreeding coefficients provided larger effects on all reproductive traits than [Formula: see text]. In particular, for CD, all estimated regression coefficients for genome-based inbreeding coefficients were significant, and for GL, that for [Formula: see text] had a significant.. Although there were no significant effects when using overall genome-level inbreeding coefficients for AFC and GL, [Formula: see text] provided significant effects at chromosomal level in four chromosomes for AFC, three chromosomes for CD, and two chromosomes for GL. In addition, similar results were obtained for [Formula: see text]. CONCLUSIONS Genome-based inbreeding coefficients can capture more phenotypic variation than [Formula: see text]. In particular, [Formula: see text] and [Formula: see text] can be considered good estimators for quantifying inbreeding level and identifying inbreeding depression at the chromosome level. These findings might improve the quantification of inbreeding and breeding programs using genome-based inbreeding coefficients.
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Affiliation(s)
- Motohide Nishio
- Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, 3050901, Japan.
| | - Keiichi Inoue
- University of Miyazaki, Miyazaki, Miyazaki, 889-2192, Japan
- National Livestock Breeding Center, Nishigo, Fukushima, 961-8511, Japan
| | - Shinichiro Ogawa
- Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, 3050901, Japan
| | - Kasumi Ichinoseki
- National Livestock Breeding Center, Nishigo, Fukushima, 961-8511, Japan
| | - Aisaku Arakawa
- Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, 3050901, Japan
| | - Yo Fukuzawa
- Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, 3050901, Japan
| | - Toshihiro Okamura
- Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, 3050901, Japan
| | - Eiji Kobayashi
- Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, 3050901, Japan
| | - Masaaki Taniguchi
- Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, 3050901, Japan
| | - Mika Oe
- Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, 3050901, Japan
| | - Kazuo Ishii
- Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, 3050901, Japan
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