Avian chromosome study in Thailand; I: some molecular cytogenetic markers and classical chromosomal features of Streptopelia chinensis (Columbidae) and Tachybaptus ruficollis (Podicipedidae)

Abstract

This study analyzed the karyological features of two bird species – Streptopelia chinensis and Tachybaptus ruficollis – from Northeastern Thailand. Mitotic chromosomes were indirectly prepared by fibroblast cell culture. The chromosomes were stained by conventional Giemsa staining and microsatellite repeat of fluorescence in situ hybridization techniques. Giemsa staining showed that the diploid chromosome number of S. chinensis was 2n=70 and T. ruficollis was 60. The types of chromosomes observed in S. chinensis were 4 large metacentric, 2 medium acrocentric, 2 small metacentric, 2 small submetacentric, 2 sex chromosomes and 58 microchromosomes; the karyotype of T. ruficollis comprised 2 large metacentric, 2 large submetacentric, 2 large acrocentric, 8 small metacentric, 4 small submetacentric, ZW sex chromosomes and 40 microchromosomes. The molecular cytogenetical features that were exhibited only on the male T. ruficollis chromosome included two microsatellites and telomeric sequences: two signals of d(CA)15 on two microchromosomes, one signal of d(GC)15 on one of the first pair, and signals of AGGGTTn sequences on each telomeric region of all macro- and microchromosomes. The karyotype formula was deduced as: 2n (70) = Lm4 + Ma2 + Sm2 + Ssm2 + 2 sex chromosomes (Sm1/Ssm1) + 58 microchromosomes for S. chinensis and 2n (60) = Lm2 +Lsm2 + La2 + Sm8 + Ssm4 + Z (Msm1) W (Ssm1) + 40 microchromosomes for T. ruficollis.

Keywords

• Streptopelia chinensis
• Tachybaptus ruficollis
• Bird chromosome
• Bird karyotype