Gene Conversion Alone Accounts for More than 90% of Recombination Events at the Am Locus of Neurospora Crassa

AUTOR(ES)

Bowring, F. J.

RESUMO

We have used closely flanking molecular markers located ~4 kb distal and 6 kb proximal of the am locus to investigate the incidence of crossover events associated with the generation of prototrophic recombinants in a cross heteroallelic am(1) am(6). Ninety-three percent of prototrophs were generated by events that did not recombine the molecular markers, indicating that simple conversion accounts for the formation of most prototrophs and that associated crossovers are much less frequent (~0.07) than estimated previously using more distant flanking markers. This suggests that conversion and crossing over during meiosis may arise from distinct mechanisms or that if, as is widely supposed, conversion and crossing over result from alternate modes of resolution of Holliday junctions then, at least for the am locus of Neurospora, the mode of resolution is strongly biased in favor of retaining the parental association of flanking sequences. Because estimates of the association of conversion and crossing over based on more distant gene markers are similar for yeast and Neurospora (~0.35), our observation may have general significance.

Documentos Relacionados

• Apolipoprotein(a) gene accounts for greater than 90% of the variation in plasma lipoprotein(a) concentrations.
• Mutation at the am Locus of NEUROSPORA CRASSA
• High Negative Interference at the Am Locus in Neurospora Crassa
• Genetic Control of Allelic Recombination at the Histidine-3 Locus of NEUROSPORA CRASSA
• An Unstable Allele of the am Locus of NEUROSPORA CRASSA