Segregational mechanisms of sex chromosomes in Spongilla-flies (Neuroptera: Sisyridae)

✍ Scribed by Sally Hughes-Schrader

• Publisher: Springer
• Year: 1975
• Tongue: English
• Weight: 633 KB
• Volume: 52
• Category: Article
• ISSN: 0009-5915
• DOI: 10.1007/bf00285784

✦ Synopsis

Evolutionary loss of the Y chromosome has occurred in Climacia areolaris (Hagen) of the neuropteran family Sisyridae. The diploid set comprises 6 pairs of autosomes, plus 2 X chromosomes in the female and 1 X in the male. The Y is retained in Sisyra vicaria (Walker) of the same family: its chromosome number is 14 in both sexes including 2X chromosomes in the female and 1X plus Y in the male. Two alternative pathways for the segregation of the sex chromosomes-distance segregation and sex bivalent formation-co-exist in the latter species in a ratio of approximately 1 to 6; the possible phylogenetic significance of this feature is discussed.