RESUMO
BACKGROUND: Nellore cattle (Bos indicus) are well-known for their adaptation to warm and humid environments. Hair length and coat color may impact heat tolerance. The Nellore breed has been strongly selected for white coat, but bulls generally exhibit darker hair ranging from light grey to black on the head, neck, hump, and knees. Given the potential contribution of coat color variation to the adaptation of cattle populations to tropical and sub-tropical environments, our aim was to map positional and functional candidate genetic variants associated with darkness of hair coat (DHC) in Nellore bulls. RESULTS: We performed a genome-wide association study (GWAS) for DHC using data from 432 Nellore bulls that were genotyped for more than 777 k single nucleotide polymorphism (SNP) markers. A single major association signal was detected in the vicinity of the agouti signaling protein gene (ASIP). The analysis of whole-genome sequence (WGS) data from 21 bulls revealed functional variants that are associated with DHC, including a structural rearrangement involving ASIP (ASIP-SV1). We further characterized this structural variant using Oxford Nanopore sequencing data from 13 Australian Brahman heifers, which share ancestry with Nellore cattle; we found that this variant originates from a 1155-bp deletion followed by an insertion of a transposable element of more than 150 bp that may impact the recruitment of ASIP non-coding exons. CONCLUSIONS: Our results indicate that the variant ASIP sequence causes darker coat pigmentation on specific parts of the body, most likely through a decreased expression of ASIP and consequently an increased production of eumelanin.
Assuntos
Proteína Agouti Sinalizadora/genética , Bovinos/genética , Pigmentação/genética , Polimorfismo Genético , Pelo Animal/metabolismo , Animais , Elementos de DNA Transponíveis , Mutação INDEL , Melaninas/genética , Melaninas/metabolismoRESUMO
The aim of this study was to investigate the occurrence of Tritrichomonas foetus in cats in the area surrounding the city of Araçatuba municipality, State of São Paulo, Brazil. Fecal samples from 129 cats were collected by rectal flush technique. It was compared two diagnosis methods, direct examination of feces and PCR. The presence of T. foetus DNA was verified using PCR by amplification of 347-bp fragment from the primers TFR3 and TFR4 and amplicons of positive cases were sequenced. Statistical analyses were performed investigating the associations between T. foetus infection with gender, age, breed, presence of diarrhea and/or history of diarrhea, previous treatment, lifestyle, origin, environment, and co-infection. T. foetus was observed in one sample (n=129) by direct microscopic examination of feces while PCR was positive in five samples (3.9%). Giardia species and Cryptosporidium species co-infection was also observed. Statistical analyses showed no significant associations between T. foetus infection and all listed factors, although most positive cats were asymptomatic and lived in multi-cat household. The isolates of T. foetus showed 100% identical sequences with other T. foetus isolates from cats around the world. So, the occurrence of T. foetus was confirmed in cats in Araçatuba city (Brazil). This parasite must be considered as a differential diagnosis in cats with diarrhea and also in asymptomatic carriers as source of infection in multi-cat environments.(AU)
O objetivo deste estudo foi investigar a ocorrência de Tritrichomonas foetus em gatos na região do município de Araçatuba, SP, Brasil. Foram coletadas amostras fecais de 129 gatos através da técnica de lavado retal. Dois métodos diagnósticos foram comparados, o exame direto das fezes e a PCR. A presença de DNA de T. foetus foi verificada por meio da PCR através da amplificação de 347 pares de bases a partir dos iniciadores específicos TFR3 e TFR4. Posteriormente, os resultados amplificados das amostras positivas foram sequenciadas. Também foi feita análise estatística a fim de investigar a correlação entre infecção por T. foetus e sexo, idade, raça, presença e/ou histórico de diarreia, tratamento prévio, coinfecção, estilo de vida, origem e tipo de ambiente. O protozoário pôde ser observado em uma amostra através do exame direto das fezes e à PCR foram detectadas cinco amostras positivas (3.9%). Foram detectadas coinfecções por Giardia spp. e Cryptosporidium spp. Não foram observadas correlações entre infecção por T. foetus e todos os fatores listados anteriormente, embora a maioria dos felinos positivos fossem assintomáticos e vivessem em ambientes multigatos. O resultado do sequenciamento genético dos isolados das amostras positivas mostrou 100% de similaridade com outros isolados de felinos no mundo. Assim, a ocorrência de T. foetus foi confirmada em gatos em Araçatuba, São Paulo, Brasil. Sendo assim, o parasito deve considerado como diagnóstico diferencial em gatos com diarreia assim como em portadores assintomáticos como fontes de infecção em ambientes multigatos.(AU)
