Table of Contents

cover image

Volume 20, Number 11
01 June 2001

pp 2611-2986

Cover. The image shows a colony of the yeast, Saccharomyces cerevisiae, engineered to display donor preference---the cell-type specific regulation of intrachromosomal recombination events underlying mating-type switching. The strain's genotype permits cells to remain switching haploids while displaying their mating type via their colouration: a-cells are white and alpha-cells are red. The strain's distribution of donor alleles, HMLa and HMRalpha, in concert with donor preference, results in 'futile' switching: a-cells use the HMLa donor and alpha-cells use the HMRalpha donor. Colony sectoring is thus a reflection of the fidelity of donor preference. The image was taken on a Wild M5 microscope. Cathy J.Wedeen and Richard Kostriken are faculty members in the Biology Department at Mills College, Oakland, CA. Their interests include the interplay of chromosome structure and function. For further details, see Kostriken and Wedeen, pages 2907--2913.

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