Partner choice in heterologous chromosome segregation of the Y chromosome in competitive situations in the oocyte ofDrosophila melanogaster

✍ Scribed by P. Portin

• Publisher: Springer Netherlands
• Year: 1992
• Tongue: English
• Weight: 452 KB
• Volume: 85
• Category: Article
• ISSN: 0016-6707
• DOI: 10.1007/bf00120320

✦ Synopsis

Heterologous segregation of the Y chromosome and secondary non-disjunction of the X chromosomes in female meiosis of Drosophila melanogaster was investigated in ten different crosses where different constellations of translocation/inversion or translocation/translocation systems of the large autosomes were present in the female parent. It appeared that the Y chromosome always segregates from the shortest of the possible heterologous pairing partners. This may be due to size-dependent mechanism of so-called 'distributive disjunction' or to the possibility that the shorter the chromosome element is, the more easily it moves in the nucleus of the oocyte. Secondary non-disjunction of the X chromosomes appeared to be lower the more possible autosomal pairing partners the Y chromosome had, suggesting that the autosomes effectively compete with the X chromosomes for pairing with the Y chromosome. An alternative explanation is that, due to interchromosomal effect on recombination, crossing over in the X chromosomes was different in different experiments.