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Y chromosome variants in cattle Bos taurus and Bos indicus

1982; Springer Nature; Volume: 14; Issue: 1 Linguagem: Inglês

10.1051/gse

2056-4554

C. R. E. Halnan, Janine I. WATSON,

Animal Genetics and Reproduction

Summary It is shown that comparison of the size of the Y chromosome between individuals may be made as reliably by computation of measurement relative to the X chromosome as by proportionation relative to the genome in the cell. By either method agreement was found with previous studies : first in placing the Y in the size range, for the cattle karyotype, between autosomes 22 and 26 ; second by finding the Y in the Charolais breed to be larger than other breeds. The value of the C-band method for recognition of the Y in Bos indicus, in particular, is reaffirmed and acridine orange is used to confirm the hypothesis of pericentric inversion as the basis of the relationship between the Y of Bos indicus and that of Bos taurus. The G-band pattern showed seven discernable regions in either species, so that the terminal part of the q arm in Bos indicus is homologous with the p arm in Bos taurus. The overall size and centromeric index of the Y are defined for each of 18 breeds of Bos taurus and 8 breeds of Bos indicus. It was found that the Y might be expected to be distinctive in certain breeds or groups : Afrikander, Augus, Claarolais, Friesian, Guern.rey, Hereford, Jersey, Murray Grey, Shorthorn and Simmental. Furthermore the Y of Simmental bulls was found to be of the same order of size as that of Charolais, although differing in centromeric index, whilst the Romagnola Y was found to be one of the smallest of Bos taurus Y chromosomes. The Y in Bos indicus was found to have short p arms in a subtelocentric conformation, in a select group of Sahiwal ; other breeds also had subtelocentric rather than terminal point centromere in the Y. The Y is established as a marker for paternal descent in defined cases.