Chromosomes and sex determination in 13 araneid spiders of North-Eastern India
✍ Scribed by S. N. Datta; K. Chatterjee
- Publisher
- Springer Netherlands
- Year
- 1988
- Tongue
- English
- Weight
- 685 KB
- Volume
- 76
- Category
- Article
- ISSN
- 0016-6707
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✦ Synopsis
The diploid chromosome number of 13 species belonging to the family Araneidae (Araneae) ranges between 16 and 25. The cr sex-determining mechanism seems to be X1X2X3X40 in one species; XIX2X30 in three species and XIX20 in the remaining 9 species. The X1X2X3X4 O, o' sex-determining mechanism is reported for the first time in spiders. All the chromosomes are with terminal centromeres. C-band preparations in 5 species suggest procentric localization of constitutive heterochromatin in all the chromosomes, though distally located C-band positive blocks are also visible in a few chromosomes. It is suggested that chromosomal evolution in this family has taken place by gradual reduction in diploid number through tandem/centric fusion followed by pericentric inversion in autosomes and nondisj unction/duplication of one X, with subsequent loss of homology in sex chromosomes.