Reciprocal chromosome translocation, rcp(7;17)(q26;q11), in a boar giving reduced litter size and increased rate of piglets dying in the early life.
Cytogenetic investigations in a boar causing a 41% reduction in litter size and also producing piglets that died soon after birth revealed the presence of a reciprocal chromosome translocation, rcp(7;17)(q26;q11). The translocation resulted in one extremely small telocentric chromosome marker. Synaptonemal complex analysis of spread spermatocytes by electron microscopy revealed an unusual behaviour of the translocation. This formed not only different types of quadrivalents (78.1% of the cells), similar to those previously found in boars heterozygous for reciprocal exchanges, but also completely or incompletely paired trivalent configurations, plus univalent (21.9%). Association between the sex bivalent and the translocation configuration was observed (18.7%), but testicular histology was normal. Furthermore, the boar with the translocation was found to produce tertiary monosomy and trisomy in some of the liveborn piglets. Some of the tertiary monosomic offspring, which died in the early extra-uterine life, demonstrated ventricular septal defect and cleft palate.
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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Villagómez
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Gustavsson
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Jönsson
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Plöen
D000818:Animals; D000013:Congenital Abnormalities / Q000235:genetics / Q000401:mortality / Q000662:veterinary; D005260:Female; D007621:Karyotyping / Q000662:veterinary; D008098:Litter Size / Q000235:genetics*; D008297:Male; D008540:Meiosis / Q000235:genetics; D008854:Microscopy, Electron; D009026:Mortality; D013552:Swine / Q000235:genetics*; D013573:Synaptonemal Complex; D013737:Testis / Q000033:anatomy & histology; D014178:Translocation, Genetic