SHORT ALLELE DOMINANCE AS A SOURCE OF HETEROZYGOTE DEFICIENCY AT MICROSATELLITE LOCI - EXPERIMENTAL-EVIDENCE AT THE DINUCLEOTIDE LOCUS GV1CT IN GRACILARIA-GRACILIS (RHODOPHYTA)

In this study, we compared the genotypes obtained at a microsatellite locus using two methods of amplification and detection of variation in a set of individuals belonging to the red alga haplo-diploid species, Gracilaria gracilis. The methods varied in their capacity to detect l onger alleles in heterozygotes, resulting in an apparent heterozygote deficiency. We attributed this bias in favour of short alleles to comp etition leading to the preferential amplification of shorter alleles ( short allele dominance). To test this hypothesis, we created artificia l heterozygotes (mixtures of two haploid DNA samples) and showed that long alleles already less intense than short alleles, 'suffer' more fr om being in association.