Standardization of MspI and HaeIII restriction karyotypes in cattle. Hereditas 140

Cattle chromosomes were digested with two restriction endonucleases, Msp I and Hae III. The banding pattern induced by each enzyme allowed the identification and paring of all individual chromosomes and consequently the elaboration of the karyotype. This method is rapid and technically easy, and proved to be of great utility in cattle cytogenetic studies. The first standard G-banded karyotype in domestic cattle (Bos taurus L., 2n /60) was established during the Reading Conference in 1976 (FORD et al. 1980). Since then cattle chromosomes have been extensively studied using G-, Q- and R- banding. Nevertheless, the elaboration of a karyotype in cattle is still a difficult task, because of the high chromosome number, the acrocentric structure of all autosomes and specially the similar banding pattern present in many chromosomes which make them difficult to identify (DI BERARDINO et al. 1990). Chromosome digestion with restriction endonucleases (RE) has been used to induce banding in many different animal species. In cattle, restriction enzymes were used mainly to characterise the structure and variability of centromeric heterochromatin (HIDAS 1995; CHAVES et al. 2000). Here, we report the results of the digestion of cattle chromosomes with two endonucleases: Msp I and Hae III. The bands induced by these enzymes allow the identification of all chromosomes, and consequently, the elaboration of the karyotype. The interest of this technique for cattle cytogeneticists is discussed