Original Article
Heredity (2002) 88, 356–360. DOI: 10.1038/sj.hdy.6800061
B-chromosomes and male-biased sex ratio with paternal inheritance in the fairy shrimp Branchipus schaefferi (Crustacea, Anostraca)
L Beladjal1, T T M Vandekerckhove1,2, B Muyssen1, J Heyrman1, J de Caesemaeker1 and J Mertens1
- 1Laboratorium voor Ecologie (WE11V), Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
- 2Laboratorium voor Microbiologie (WE10V), Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
Correspondence: Dr L Beladjal, Ghent University, Lab. Animal Ecology, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium. E-mail: lynda.beladjal@rug.ac.be
Received 29 December 2000; Accepted 15 January 2002.
Abstract
This study reports on male-biased sex ratios in west Mediterranean populations of the freshwater anostracan Branchipus schaefferi (Crustacea, Anostraca, Branchipodidae), in contrast to populations elsewhere. Crossing experiments over several generations indicate a clear paternal inheritance of the trait, possibly with a dosage effect. Various mechanisms which may underlie this phenomenon are discussed, the most plausible being the presence of one or more supernumerary ('B') chromosomes – as evidenced by karyological observations – interfering with sex determination and probably having an accumulation mechanism in male individuals.
Keywords:
B-chromosomes, sex ratio distortion, paternal inheritance, Branchipus schaefferi, Crustacea, Anostraca
