| Research Abstract |
(1) Development of DNA probes for identification of sexes of Carinatae species of birds : A non-repetitive genomic DNA fragment, EE0.6, from the chicken W chromosome was clones. The EE0.6 sequence was shown to be conserved widely on the avian W chromosome, and PCR using a set of primers from this sequence amplified a female-specific band in a number of Carinatae species. However, in some species, like Oriental white stork (Ciconia boyciana), a homologous sequence to EE0.6 was also found on the Z chromosome. The two EE0.6-related sequences ; XH0.6 on the W chromosome and XH0.6RSM on the Z chromosome, were cloned from C. boyciana, and PCR using sets of primers from XH0.6 and XH0.6RSM amplified a female-specific band form the W chromosome and male-female-common bands from the Z chromosome from the genomic DNA preparations of C. boyciana.
(2) Identification of sex chromosomes of Ratitae birds : Homologous genomic sequences to the chicken EE0.6 (on the W chromosome) and the chicken IREBP and
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ZOV3 genes (both on the Z chromosome) were cloned from genomic DNAs of ostrich and emu. Those three sequences from the Ratitae species maintained 71-92% identities to those of the chicken counterparts. Fluorescence in situ hybridization (FISH) using these cloned sequences from the Ratitae, demonstrated that all the three sequences were localized on a particular set of chromosomes in ostrich, emu and cassowary. However, the IREBP sequence was missing from one of the pairs in the female ostrich and the female cassowary. These results demonstrated that sex chromosomes of both Carinatae and Ratitae birds were evolved from the common ancestral pairs of chromosomes and that a little differentiation of W chromosome was evident in the ostrich and the cassowary.
(3) Application to the mating program of endangered avian species : PCR amplification of the female-specific and the male-female-common bands using the sets of primers from the above XH0.6 and XH0.6RSM of C. boyciana, respectively, was also successful for Nipponia, an endangered species of lbis, using the genomic DNA prepared from a few feathers. Less
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