Yeast strain for visual screening for the two reciprocal products of mitotic crossing over
A strain of Saccharomyces cerevisiae, D/sub 5/, is described that allows for rapid, visual screening for mitotic crossing over in colonies on solid media. D/sub 5/ carries two phenotypically- distinguishable and recessive alleles of the gene ade2. One allele, ade2119, causes a leaky requirement for adenine, and a pink coloration of colonies. The other allele, ade2-40, causes a complete requirement for adenine and the formation of deeply red colonies. The two alleles complement each other to the effect that D/sub 5/ forms white colonies and does not require adenine for growth. Mitotic crossing over generates two reciprocal products that show up together in colonies as pink and red sectors, twin-spotted colonies. Such twin-spotted colonies were obtained after treatment with ultraviolet light, gamma rays, and ethyl methanesulfonate (EMS). Tetrad analysis was performed with cells isolated from the red and the pink half of twin- spotted colonies. The results showed that the pink sectors had bacome homozygous for allele ade2--119, the red sectors were homozygous for the other allele, ade2- 40. With one exception, other markers present in D/sub 5/ in a heterozygous condition were still heterozygous. ln addition to twin-spotted colonies, colonies with white and red or white and pink and even with red, white and pink sectors as well as completely pink or completely red colonies were found. These can be interpreted to result from a variety of mechanisms other than mitotic crossing over that are mentioned in the discussion.
- Research Organization:
- Brooklyn Coll.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-29-005302
- OSTI ID:
- 4387254
- Journal Information:
- Mutat. Res., v. 21, no. 5, pp. 263-269, Other Information: Orig. Receipt Date: 30-JUN-74
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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