High genetic load in the Pacific oyster Crassostrea gigas.
The causes of inbreeding depression and the converse phenomenon of heterosis or hybrid vigor remain poorly understood despite their scientific and agricultural importance. In bivalve molluscs, related phenomena, marker-associated heterosis and distortion of marker segregation ratios, have been widel...
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ftpubmed:oai:pubmedcentral.nih.gov:1461778 2023-05-15T15:58:41+02:00 High genetic load in the Pacific oyster Crassostrea gigas. Launey, S Hedgecock, D 2001-09 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1461778 http://www.ncbi.nlm.nih.gov/pubmed/11560902 en eng http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1461778 http://www.ncbi.nlm.nih.gov/pubmed/11560902 Research Article Text 2001 ftpubmed 2013-08-31T01:33:15Z The causes of inbreeding depression and the converse phenomenon of heterosis or hybrid vigor remain poorly understood despite their scientific and agricultural importance. In bivalve molluscs, related phenomena, marker-associated heterosis and distortion of marker segregation ratios, have been widely reported over the past 25 years. A large load of deleterious recessive mutations could explain both phenomena, according to the dominance hypothesis of heterosis. Using inbred lines derived from a natural population of Pacific oysters and classical crossbreeding experiments, we compare the segregation ratios of microsatellite DNA markers at 6 hr and 2-3 months postfertilization in F(2) or F(3) hybrid families. We find evidence for strong and widespread selection against identical-by-descent marker homozygotes. The marker segregation data, when fit to models of selection against linked deleterious recessive mutations and extrapolated to the whole genome, suggest that the wild founders of inbred lines carried a minimum of 8-14 highly deleterious recessive mutations. This evidence for a high genetic load strongly supports the dominance theory of heterosis and inbreeding depression and establishes the oyster as an animal model for understanding the genetic and physiological causes of these economically important phenomena. Text Crassostrea gigas Pacific oyster PubMed Central (PMC) Pacific |
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Research Article Launey, S Hedgecock, D High genetic load in the Pacific oyster Crassostrea gigas. |
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Research Article |
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The causes of inbreeding depression and the converse phenomenon of heterosis or hybrid vigor remain poorly understood despite their scientific and agricultural importance. In bivalve molluscs, related phenomena, marker-associated heterosis and distortion of marker segregation ratios, have been widely reported over the past 25 years. A large load of deleterious recessive mutations could explain both phenomena, according to the dominance hypothesis of heterosis. Using inbred lines derived from a natural population of Pacific oysters and classical crossbreeding experiments, we compare the segregation ratios of microsatellite DNA markers at 6 hr and 2-3 months postfertilization in F(2) or F(3) hybrid families. We find evidence for strong and widespread selection against identical-by-descent marker homozygotes. The marker segregation data, when fit to models of selection against linked deleterious recessive mutations and extrapolated to the whole genome, suggest that the wild founders of inbred lines carried a minimum of 8-14 highly deleterious recessive mutations. This evidence for a high genetic load strongly supports the dominance theory of heterosis and inbreeding depression and establishes the oyster as an animal model for understanding the genetic and physiological causes of these economically important phenomena. |
format |
Text |
author |
Launey, S Hedgecock, D |
author_facet |
Launey, S Hedgecock, D |
author_sort |
Launey, S |
title |
High genetic load in the Pacific oyster Crassostrea gigas. |
title_short |
High genetic load in the Pacific oyster Crassostrea gigas. |
title_full |
High genetic load in the Pacific oyster Crassostrea gigas. |
title_fullStr |
High genetic load in the Pacific oyster Crassostrea gigas. |
title_full_unstemmed |
High genetic load in the Pacific oyster Crassostrea gigas. |
title_sort |
high genetic load in the pacific oyster crassostrea gigas. |
publishDate |
2001 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1461778 http://www.ncbi.nlm.nih.gov/pubmed/11560902 |
geographic |
Pacific |
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Pacific |
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Crassostrea gigas Pacific oyster |
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Crassostrea gigas Pacific oyster |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1461778 http://www.ncbi.nlm.nih.gov/pubmed/11560902 |
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1766394455901863936 |