CYTOGENETIC ANALYSlS OF NEOTOMA MEXICANA TORQUATA

Resumen

This work reports the cytogenetic analysis of Neotoma mexicana torquata, a subspecies restricted to the southern part of the Valley of Mexico. The complement shows a chromosome number 2n=52 and a fundamental number FN=52. The karyotype of this subspecies is near but little different from that showed by other populations of Neotoma mexicana reported previously. During meiosis at pachytene the homologue chromosomes form 26 bivalent rings. The sex-chromosomes shows a small terminal pairing segment forming an end to end X-Y complex.