Diatoms are very promising from a biotechnological point of view (biofuels, food & feed, …).
One of the main bottlenecks for diatom cultivation lies however in their life cycle, characterized by gradual size reduction which ultimately leads to programmed cell death. Cell size recovery is only possible when sexual reproduction occurs (Lewis, 1984; Chepurnov et al., 2004). So far, however, hardly anything is known about the molecular base of sexual reproduction and sex determination in diatoms. Seminavis robusta is one of the few diatoms having a heterothallic (dioecy) mating system where two mating types exist (Chepurnov et al., 2002). Currently, we are generating a AFLP-based genetic map of the Seminavis robusta genome using a F1 mapping population derived from a cross between two hetorozygous strains (H73A and 96A). The 116 heterozygous F1 offspring have been genotyped with AFLP and phenotyped for mating type. The small sample size of 116 segregants, however, will not allow us to fine-map the MT locus. Therefore, the current linkage mapping will be complemented with an additional strategy, called Bulked Segregant Analysis (BSA), to fine-map the MT locus. Allelic reads showing the highest differences in allelic count will be mapped on the genome sequence and checked for co-segregation with the MT phenotype by linkage analysis. This will eventually result in the identification of the MT locus.