Interchromosome effects on chiasma frequencies in rye

Abstract

In interchange heterozygotes and interchange trisomics of rye (Secale cereale) correlations between multivalents and bivalents in respect of number of chromosome arm pairs bound at MI, were studied. No significant positive correlations were observed. Significant negative correlations, indicating interchromosome effects, were found only in cell populations that approached anaphase. The effects seem to be generated by non-random loss of chiasmata from chromosome ends. The absence of demonstrable real interchromosome effects on chiasma formation in the material studied may be explained by positive correlations (due to between-cells variation) counteracting possible negative correlations. Another explanation may be found in the fact that intra-chromosome interference, that might be one of the ways through which interchromosome effects act, does not come to expression with the methods of observations used.