Abstract
Chromosome patterns in excised gonads from laboratory-reared Mexican Boophilus annulatus (Say), B. microplus (Canestrini) and their reciprocal F₁ hybrids were studied. Mitotic and meiotic divisions were observed in males of both species, but hybrid males, with a possible exception, exhibited only mitotic cells. Females of both species possessed only mitotic oogonia, with one exception, but hybrid female tissue contained both mitotic and meiotic cells. Both species possessed 10 pairs of autosomes plus one and two near-homomorphic sex chromosomes in males and females, respectively. All chromosomes appeared to possess terminal centromeres. B. annulatus autosomes ranged from 1.43 to 2.87 microns in length, and the sex chromosomes averaged 7.1 microns in the males and 6.5 and 7.0 microns in the females. Autosomes in B. microplus ranged from 2.29 to 4.86 microns in length, the male sex chromosome averaged 5.58 microns and the near-homomorphic sex chromosomes in females ranged from approximately 1.5X to 4X the length of the autosomes. Sex determination in both species is by an XX:XO mechanism. ...
Newton, Weldon Harrison (1969). Chromosome patterns of Boophilus annulatus, Boophilus microplus and their F₁ hybrids. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -776330.