Banded karyotype of Nelore cattle (Bos taurus indicus Linnaeus, 1758).

Andréia Pires Amancio,Rafael Carneiro Silvafael,Sabrina Sara Moreira Duarte,Danilo Conrado Silva,Aparecido Divino Da Cruz,Claudio Carlos Da Silva,Alex Silva Da Cruz

doi:10.3897/compcytogen.v13i3.36449

Andréia Pires Amancio, Rafael Carneiro Silvafael + Show 5 more

Open Access

https://doi.org/10.3897/compcytogen.v13i3.36449

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Abstract

Chromosome banding techniques were applied and standardized to obtain karyotype characteristics for the first time in Brazil of Nelore cattle – Bos taurus indicus Linnaeus, 1758 – (bovine subspecies most prominent in Brazilian livestock). Blood samples were collected from the animals of the School of Agrarian and Biological Sciences of the Pontifical Catholic University of Goiás, two males and two females of pure breed. These samples were submitted to the cell culture method to study metaphase chromosomes. Chromosome banding techniques (C, G and NOR) revealed the karyotype architecture of Nelore cattle common with that of other breeds of zebu cattle formerly karyotyped. The diploid chromosome number was invariably normal, 2n = 60. C-banding revealed C-positive heterochromatin in centromeric regions almost in all chromosomes. G-banding presented the expected band pattern in the respective chromosome pairs in correspondence with the established chromosomal patterns for the species. Ag-staining for nucleolus organizer regions (AgNOR) was identified on the telomeric end of the long arm in 7 autosomal chromosomes. In this study we found more regions in chromosomes with staining than presented in the literature for the Bos indicus group (BIN). These NOR regions were repeated on the same chromosomes for the 4 animals studied.

Highlights

Nelore is an important bovine breed and well noted in Brazil for its meat production, body size and sturdiness
The study of Brazilian Nelore cattle adds to the list of the zebu (B. t. indicus) breeds so far karylogically investigated
About 80% of the Brazilian herd is composed of zebu breeds (Bos t. indicus), animals with more rusticity and easy adaptation to the predominant environment in the country (Amaral et al 2012)

Summary

Introduction

Nelore is an important bovine breed and well noted in Brazil for its meat production, body size and sturdiness. In the last 5 years, with respect to meat production, the cross between Angus (taurine) and Nelore (zebu) breeds has been growing in Brazil. The conservation of the original breed is necessary (Reddy et al 2016). Despite this trend in the market, Nelore still comprises up to 80% of the national cattle of bovine breeds raised for meat, mostly due to its combination of productivity and adaptability to the tropics (Júnior et al 2016). The states of Mato Grosso, Mato Grosso do Sul, and Goiás, a region known as Central Brazil, hold 43% of the country bovine cattle composed of Nelore breed (IBGE 2017)

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