Autori: Marius Cirlan

Editorial: S. Karger, Cytogenetics and Cell Genetics(Abstracts of papers,Second European Cytogenetics Conference, Vienna,Austria,July 3-6,1999), vol. 85, p.p. 17, 1999.

Rezumat:

One-day chicks affected by microphthalmia and/or anophthalmia associated with crossed beak have cytoegenetically been examined. Chromosome preparations were made from bone marrow, and ASG-banding techique has been applied. Examinations of metaphase cells evidenced two types of cell lines chromosomally different. It was established that the analysed chicks were haploid-diploid chimeras. All haploid cells contained a Z gonosome. The lack of 1A-W cells indicate that,like other investigators remarked, the supernumerary spermatozoa are the most likely origin of the haploid cells in these chimeric chicks. Certain cytoplasmic conditions may exist in the secondary oocytes, and they allow the mitotic division of the extra spermatozoa with subsequent evolution to genetic chimerism. Although in other studies he haploid-diploid chickens were all phenotypically normal and fertile, in this report the haploid-diploids were abnormal. Since, as single conditions, earlier findings showed that microphthalmia and crossed beak are autosomal recessive traits, the association of these two anomalies could be attributed to gene mutations affecting neighbouring loci. In the same time, there is no available explanation for a link between these gene mutations and the polyspermy which is the cause of haploid cell line appearance in these haploid-diploid chimeric chicks.

Cuvinte cheie: chickens, microphthalmia, chromosomes, chimerism,anomalies