Synaptomenal complex analysis of four breeds of Bos taurus taurus x B. taurus indicus hybrids

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:19:59Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:39:12Z : No. of bitstreams: 1 2-s2.0-0034515059.pdf: 740506 bytes, checksum: 1e324d9c51ba2b46f67efb5cbce3ec43 (MD5) Made available in DSpace on 2014-05-27T11:19:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2000-12-01 Item merged in doublecheck by Felipe Arakaki (fe.arakaki@gmail.com) on 2015-11-20T17:02:49Z Item was identical to item(s): 16566, 65828 at handle(s): http://hdl.handle.net/11449/16958, http://hdl.handle.net/11449/66346 The synaptonemal complex (SC) was analyzed in four F1 hybrids of Bos taurus taurus and B. taurus indicus including Gyr-Simmental (G-S), Nelore Simmental (N-S), Gyr-Holstein-Friesian (G-H) and Nelore-Piemontese (N-P). We analysed the frequency of various types of SC abnormalities and the frequency of cells with SC abnormalities. The results were compared with similar observations made on purebred animals. All the animals studied possessed 29 autosomal and one sex bivalent. The frequency of cells with abnormalities in the hybrids were 28.0% in the N-P, 29.1% in the G-S, 33.3% in the N-S and 40.0% in the G-H. The frequency of cells with abnormalities in the four hybrids was 31.5%; 57.9% of these abnormalities occurred in zygotene and 42.0% occurred in pachytene. The comparisons among the hybrids and among the hybrids and their parental breeds showed that the only significant difference was between Gyr and Gyr-Holstein-Friesian animals. Some aspects of the relationship between the frequency of cells with anomalies and the fertility of hybrids are discussed. Departamento de Morfologia Institute de Biociencias Universidade Estadual Paulista, Botucatu, SP Departamento de Bioestatistica Institute de Biociencias Universidade Estadual Paulista, Botucatu, SP Departamento de Morjologia Instituto de Biociincias Curnpus de Botucatu, 18618-000, Botucutu, SP Departamento de Morfologia Institute de Biociencias Universidade Estadual Paulista, Botucatu, SP Departamento de Bioestatistica Institute de Biociencias Universidade Estadual Paulista, Botucatu, SP