RESUMO
Amazonian (Trichechus inunguis) and West Indian (Trichechus manatus) manatees are aquatic mammals vulnerable to extinction found in the Amazon basin and the coastal western Atlantic. Toll-like receptors (TLR) play a key role in recognizing pathogen-associated molecular patterns using leucine-rich repeats (LRRs). We described the diversity of TLR4 and TLR8 genes in these two species of manatee. Amazonian manatee showed seven SNPs in TLR4 and the eight in TLR8, while West Indian manatee shared four and six of those SNPs, respectively. In our analysis, TLR4 showed one non-conservative amino acid replacement substitution in LRR7 and LRR8, on the other hand, TLR8 was less variable and showed only conserved amino acid substitutions. Selection analysis showed that only one TLR4 site was subjected to positive selection and none in TLR8. TLR4 in manatees did not show any evidence of convergent evolution compared to species of the cetacean lineage. Differences in TLR4 and TLR8 polymorphism may be related to distinct selection by pathogens, population reduction of West Indian manatees, or an expected consequence of population expansion in Amazonian manatees. Future studies combining pathogen association and TLR polymorphism may clarify possible roles of these genes and be used for conservation purposes of manatee species.
RESUMO
Objetivou-se nesse trabalho, estimar os parâmetros genéticos para características de crescimento em ovinos da raça Santa Inês através do Método da Máxima Verossimilhança Restrita (REML). Os componentes de (co)variâncias e os parâmetros genéticos foram estimados pelo Software MTDFREML (Multiple Trait Derivative-Free Restricted Maximum Likelihood). As características avaliadas em modelos uni e bicaracterística foram: peso ao nascimento (PN) e peso ao desmame (P90). Além dos efeitos fixos de sexo, grupo contemporâneo e tipo de parto, foram utilizados os seguintes efeitos aleatórios: efeito genético aditivo direto, efeito genético aditivo materno e efeito residual. As estimativas de herdabilidade aditiva direta para PN foram 0,20 e 0,21, para os modelos uni e bicaracterística, respectivamente. As estimativas de herdabilidade aditiva direta para P90 foram 0,04 e 0,07, para os modelos uni e bicaracterística, respectivamente. A correlação genética entre PN e P90 foi de 0,11, indicando que ambas as características devem ser trabalhadas simultaneamente.
The objective of this study is to estimate genetic parameters for growth traits in sheep Santa Ines breed by Restricted Maximum Likelihood (REML). The (co)variance components and genetic parameters were estimated by MTDFREML Software (Multiple Trait Derivative-Free Restricted Maximum Likelihood). The characteristics evaluated in single and two-trait models were: birth weight (BW) and weaning weight (WW). In addition to the fixed effects of sex, contemporary group and parity type, we used the following random effects: direct genetic effect, maternal additive genetic and residual effects. The direct additive heritability estimates for BW were 0.20 and 0.21 for single and two-trait models, respectively. Heritability estimates for direct additive WW were 0.04 and 0.07 for single and two-trait models, respectively. The genetic correlation between BW and WW was 0.11, indicating that both traits should be worked on simultaneously.