STANDARDIZED KARYOTYPE AND IDIOGRAM OF THE VARIABLE SQUIRREL, Callosciurus finlaysoni bocourti (MILNE-EDWARDS, 1867) BY CONVENTIONAL STAINING TECHNIQUE

Tanomtong, A., Khunsook, S., Jantarat, S., Supanuam, P., Kenthao, A. and Kaewsri, S.. 2009.

Standardized karyotype and ideogram of the variable squirrel, Callosciurus finlaysoni bocourti (Milne-Edwards, 1867) by conventional staining technique. Thai Wildlife Journal 16(1): 83-93. [PDF] (TCI: Thai-Journal Citation Index Centre)

ABSTRACT

         Standardized karyotype and idiogram of the variable squirrel (Callosciurus finlaysoni bocourti) was studied at Khon Kaen University, Thailand. Blood samples were taken from two male and two female variable squirrels. After lymphocyte culture, the mitotic chromosome preparation was accomplished by the hypotonic-air-drying method and conventional Giemsa’s staining technique. The results showed that the number of diploid chromosomes was 2n=40 and the fundamental number (NF) was 78 in both male and female. The autosomes consisted of 4 large metacentric, 4 large submetacentric, 14 large acrocentric, 2 medium telocentric, 4 small metacentric, 6 small acrocentric and 4 small telocentric chromosomes. The X chromosome was a medium metacentric chromosome and the Y chromosome was a small metacentric chromosome. A pair of the short arm near centromere of chromosome pairs 14 showed clearly observable secondary constriction (satellite chromosomes). The chromosome marker of the variable squirrelis the chromosome pair 1 which is the largest submetacentric chromosome. The karyotype formula for the variable squirrel is as follows:

                  2n (40) = Lm4+Lsm4+La14+Mt2+Sm4+Sa6 +St4+ sex chromosomes