Genetics glossary
What is first division segregation (FDS)?
first division segregation (FDS) — The allele arrangement (4+4) of spores within an ordered ascus that indicates the lack of recombination between a locus and its centromere. A linear pattern (4+4) of spore phenotypes within an ordered ascus for a particular allele pair, produced when the alleles go into separate nuclei at the first meiotic division, showing that no crossover has occurred between that allele pair and the…
The allele arrangement (4+4) of spores within an ordered ascus that indicates the lack of recombination between a locus and its centromere. A linear pattern (4+4) of spore phenotypes within an ordered ascus for a particular allele pair, produced when the alleles go into separate nuclei at the first meiotic division, showing that no crossover has occurred between that allele pair and the centromere. See Second division segregation.