Does polyploidy lead to fewer and shorter microsatellites in Barbus (Teleostei: Cyprinidae)?
Article first published online: 31 OCT 2003
Volume 6, Issue 2, pages 169–178, February 1997
How to Cite
Chenuil, A., Desmarais, E., Pouyaud, L. and Berrebi, P. (1997), Does polyploidy lead to fewer and shorter microsatellites in Barbus (Teleostei: Cyprinidae)?. Molecular Ecology, 6: 169–178. doi: 10.1046/j.1365-294X.1997.00170.x
- Issue published online: 31 OCT 2003
- Article first published online: 31 OCT 2003
- Cited By
- repeat motif;
- slipped-strand mispairing;
- DNA amount regulation;
- slippage-deletion bias;
Screening of a hybrid Barbus barbus-B. meridionalis genome was performed for CA, GA, TAT, TCT, TAG, TGT, TATT, TACT, ATCT motifs, and simultaneously on another fish species, tilapia S. melanotheron. Sequences of positive clones were obtained for Barbus and revealed that repetitive structure significantly depends on the motif: most TAT and TATT repeats contain small numbers of repeats, and these repeats are highly heterogeneous, whereas other motifs (we mainly obtained CA and GATA repeats) form longer and much more homogeneous arrays. Polymorphism data from five loci in two different species of barbel show that perfectly repetitive loci are much more variable than imperfect loci (TAT and TATT). We compared the frequency of positive clones for different repeat motifs between barbel and tilapia. For dinucleotide repeats (CA and GA), the comparison was extended to additional fish species, trout and sea bass, which were screened in nearly identical conditions for these motifs. The most salient feature of these comparisons reveals that arrays of dinucleotide motifs are significantly under-represented and shorter in Barbus than in other fish species. We propose an explanation that can account for most features of microsatellites characterizing the genome of barbel. A bias toward deletion affecting slipped-strand mispairing events would lead to shortening and loss of microsatellite loci. Such a bias would represent an efficient way of eliminating useless DNA from polyploidized species with an excessive amount of DNA.