X/XY/XYY mosaicism as a cause of subfertility in boars: a single case study

Sex chromosome abnormalities are common in mammals and humans and are often associated with subfertility. In this study a boar with normal sperm parameters was indicated to have reduced prolificacy from figures obtained for return rate, farrowing rate and total number of piglets born. G-banded cytogenetic analysis of peripheral blood identified an abnormal mosaic sex chromosome constitution 39,XYY[74]/38,XY[23]/37,X[3]. Cytogenetic analysis of fibroblasts confirmed this mosaic karyotype with similar percentages of cell lines observed 39,XYY[76]/38,XY[19]/37,X[5]. External genitalia revealed a poorly developed scrotum with the right testicle being smaller than the left. To the best of our knowledge this is the first time that this chromosome constitution has been reported in the pig. It is of particular interest that this karyotype is associated with reduced boar fertility, which could lead to potential economic losses if such a boar were selected for breeding purposes

ESR1 and ESR2 gene markers are not associated with number of piglets born alive in Italian Large White sows

Many studies have reported that markers in the <em>estrogen</em> <em>receptor</em> <em>1</em> (<em>ESR1</em>) and <em>estrogen recepto</em>r <em>2</em> (<em>ESR2</em>) genes are associated with litter size in pigs, even if inconsistent results have been obtained in different populations. We analysed the <em>ESR1 Pvu</em>II and the <em>ESR2</em> AF164957:c.949G>A polymorphisms in Italian Large White (ITLW) sows to evaluate if these markers are associated with number of piglets born alive at first litter (NBA1). First, both polymorphisms were genotyped by selective genotyping in a total of 440 sows chosen according to the extreme and divergent estimated breeding value (EBV) for NBA1 (220 sows with low EBV and 220 sows with high EBV). For the <em>ESR1</em> polymorphism, no allele and genotype frequency differences were observed between the two groups (allele A= 0.62 and allele B= 0.38 in both two groups). For the <em>ESR2</em> polymorphism, a trend of different allele frequency between the two tails was identified (P = 0.052). However, no significant association between the same <em>ESR2</em> marker and EBV NBA1 was detected analyzing 1772 ITLW sows (allele A= 0.59 and allele G= 0.41). As the two investigated polymorphisms were not associated with NBA1 EBVs, they seem not useful for marker assisted selection to improve this trait in the ITLW breed

Efeito da herança citoplasmática sobre características de produção em ovinos da raça merino Effects of cytoplasm inheritance on production traits of merino sheep

Para avaliar os efeitos de linhagem citoplasmática (LCT), foram usadas medidas de peso corporal (PC, n = 707) e peso de velo sujo (PVo, n = 703) de fêmeas e medidas de diâmetro das fibras de lã (DF, n = 350) de machos ovinos da raça Merino com um ano de idade. As informações de pedigree incluíram 3645 animais e, em média, 10 gerações. Foram usados a metodologia da Máxima Verossimilhança Restrita e o modelo animal que incluiu efeito genético direto, efeitos direto e de LCT, efeitos direto, materno e de LCT e efeitos direto, materno e permanente de meio materno. Efeitos fixos de ano e época de nascimento foram incluídos em todos os modelos. O teste da razão das verossimilhanças foi usado para comparar os modelos matemáticos. Não houve diferenças entre os modelos em que se incluiu ou não o efeito de LCT, indicando que os efeitos citoplasmáticos não foram importantes para as características estudadas. Para PC, os resultados indicaram haver confundimento parcial entre os efeitos genético aditivo materno, permanente de meio materno e de LCT. A importância relativa dos efeitos aditivos maternos foi maior para a característica PC (24,2%, no modelo mais simples; 7,9% no modelo mais completo) que para PVo e DF. A importância relativa dos efeitos aditivos diretos foi também maior para PC (24,5 a 37,1%, para os diferentes modelos), seguido de PVo (de 19,5 a 24,6%) e DF (de 16,3 a 21,0%). As estimativas de herdabilidade indicam que a seleção pode ser realizada com sucesso para as características peso corporal, peso de velo sujo e diâmetro das fibras de lã dos ovinos da raça Merino.<br>To evaluate the effects of cytoplasm lineage (CL) the body weight (BW, n = 707) and greasy fleece weight (FW, n = 703) of females and fiber wool diameter (FD, n = 350 males) of males sheep from yearling Merino sheep were used. The pedigree information included 3,645 animals and an average of 10 generations. The Maximum Restricted Likelihood methodology and animal models that included the direct genetic, direct and CL effects, direct, maternal and CL effects and direct, maternal, environmental maternal effects were used. Fixed effects of year and season of birth were included in all models. The likelihood ratio test was used for comparisons between the models. There were no differences between models including or not CL, indicating that CL effects were not important for the studied traits. For BW, the results indicated a partial confounding among the maternal additive genetic, environmental maternal and CL effects. The importance of maternal additive effects was greater for the BW traits (from 24.5% at least to 7.9% in the most comprehensive models) than for FW and FD. The relative importance of direct additive effects was also greater for BW (from 24.5 to 37,1%, for the different models), followed by FW (from 19.5 to 24.6%) and for FD (from16.3 to 21.0%). The heritability estimates indicated that the successful selection could be obtained for body weight, fleece weight ad fiber wool diameter of sheep Merino breed

Estimação de parâmetros genéticos em tamanho de leitegada de suínos utilizando análises de características múltiplas Estimation of genetic parameters for litter size in pigs using multi-trait analyses

Registros de animais da raça Large White foram utilizados para estimar componentes de co-variâncias e parâmetros genéticos para a característica número de leitões nascidos como medida do tamanho de leitegada. Na obtenção dos componentes de co-variâncias e dos parâmetros genéticos, utilizou-se o método da Máxima Verossimilhança Restrita, com o algoritmo Livre de Derivadas, por meio do programa MTDFREML. O modelo misto continha o efeito fixo de grupo contemporâneo e os efeitos aleatórios genético aditivo direto e residual. Dados das primeiras quatro parições foram usados em duas análises: análises unicaracterísticas e análise multicaracterística separada em séries de análises bicaracterísticas, na qual cada parição foi tratada como característica diferente. As estimativas de herdabilidades aditivas diretas para as parições obtidas nas análises multicaracterísticas foram consistentes com as estimativas obtidas nas análises unicaracterísticas, que variaram de 0,14 a 0,20. Estimativas de correlação fenotípica foram menores que as correlações genéticas. As correlações genéticas foram menores que 0,75 em todas as parições, exceto entre a terceira e a quarta parição, cuja correlação foi alta (0,91). A menor correlação genética foi observada entre a primeira e a segunda ordem de parto (0,60).<br>Data from the first four parities of Large White pigs were used to estimate (co)variance components and genetic parameters for litter size (LS) in single trait and multi-trait analyses. The (co)variance components and genetic parameters were estimated by restricted maximum likelihood using the MTDFREML program. LS in each parity was considered a different trait and the models included contemporary group as fixed effect and additive direct genetic and residual as random effects. Heritability estimates of LS in different parities in single trait analyses ranged from 0.14 to 0.20. Estimates of heritability in multi-trait analyses were similar to those obtained in single trait analyses. Phenotypic correlation estimates were lower than the genetic ones. Genetic correlations between parities were lower than 0.75, except for the estimate between the third and fourth parities, which was the highest one (0.91). The smallest genetic correlation (0.60) was observed between the first and second parities