Published online by Cambridge University Press: 14 April 2009
Meiotic chromosome associations in homothallic strains of S. cerevisiae were investigated by analysis of meiotic spore colonies and crossing over in +/+/− trisomics. The segregants of these aneuploids produce phenotypically distinguishable tetrasomic spore colonies. The data indicate that trivalent associations occur with a high frequency in trisomics of chromosome XVII and that the frequency of second division segregation is markedly increased over that found in the normal dipoid.