Homology within the X chromosomes of Boophilus microplus (Canestrini) and B. annulatus (Say)

Chromosome banding patterns of the X chromosomes of Boophilus annulatus (Say) and B. microplus (Canestrini) indicate considerable homology between the two species. All bands of the small X chromosome of B. microplus are represented in the large X chromosome of B. annulatus with the exception of one medially located dark band. A large region of material proximal to the centromere and a small segment located at the telomere of the large X chromosome of B. annulatus are not represented in the small X chromosome of B. microplus. Meiotic abnormalities and the potential differentiation/evolution of the two X chromosomes are discussed. The extensive homology between the two species supports the genic data and linkage analyses previously published for these species.