Japanese Journal of Veterinary Research;Volume 13, Number 2

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CHROMOSOME STUDIES ON HETEROSEXUAL TWINS IN CATTLE : I SEX-CHROMOSOME CHIMERISM (XX/XY)

KANAGAWA, Hiroshi;MURAMOTO, Jun-ichi;KAWATA, Keiichiro;ISHIKAWA, Tsune

Permalink : http://hdl.handle.net/2115/1806
JaLCDOI : 10.14943/jjvr.13.2.33

Abstract

The chromosome constitution of 16 cases of bovine heterosexual twins consisting of 9 freemartins, 6 males co-twined with the freemartin and one non-freemartin female, and also 15 control animals consisting of 3 homosexual twin males, 4 single born males and 8 single born females were examined in blood cultures as well as in tissue cultures from various organs. The results are summarized as follows : 1) The diploid number of chromosomes in controls was 60. The 29 autosomal pairs were acrocentric in nature, while X and Y chromosomes were submetacentric. 2) In both freemartins and their co-twins, tissue cells of mesodermal and endodermal origin generally showed 2A-XX/2A-XY chimerism. A normal cow from the non-freemartin heterosexual twins was found to possess a normal female complement of chromosomes. Cell chimerism occurring in both the freemartins and co-twins is ascribed to a cell interchange as a result of vascular anastomosis.

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