Natural translocation of a large segment of chromosome III to chromosome I in a laboratory strain of Saccharomyces cerevisiae.
We have investigated chromosomal segregation during meiosis in a cross between two polymorphic haploid laboratory strains of Saccharomyces cerevisiae, FL100 and GRF18. These two strains have large chromosome-length polymorphisms for chromosomes I and III allowing for easy scoring of parental chromosomes after meiotic segregation. Chromosome III in the FL100 strain was 35 kb shorter than chromosome III in GRF18, while FL100 chromosome I was 40 kb larger than chromosome I in GRF18. Segregation analysis of chromosomes I and III in 50 tetrads showed an apparent association between chromosomes I and III, whereas only the original parental association of chromosomes I and III was found in the spores. By hybridization with chromosome-specific probes we have shown that the polymorphisms are due to a large translocation from chromosome III onto chromosome I in FL100. The translocated fragment is larger than 80 kb and was mapped between Ty and HML. In nine tetrads analyzed, chromosome-length polymorphisms which did not segregate according to Mendelian law were observed.
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Institut de Biologie Moléculaire et Cellulaire du C.N.R.S., 15, rue René Descartes, F-67084 Strasbourg, France.
D015139:Blotting, Southern; D002874:Chromosome Mapping; D015825:Chromosomes, Fungal; D015342:DNA Probes; D007621:Karyotyping; D008540:Meiosis; D011110:Polymorphism, Genetic; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D013172:Spores, Fungal; D014178:Translocation, Genetic
D015342:DNA Probes