Chimeric types of chromosome X in bottom-fermenting yeasts.
OBJECTIVE
To determine the structure of the chimeric chromosome X of bottom-fermenting yeasts.


RESULTS
Eight cosmid clones carrying DNA from chromosome X of bottom-fermenting yeasts were selected by end-sequencing. Four of the cosmid clones had Saccharomyces cerevisiae (SC)-type and Saccharomyces bayanus (SB)-type chimeric ends, two had SC-type ends and two had SB-type ends. Sequencing revealed that the bottom-fermenting yeast strains in this study had four types of chromosome X: SC-SC, SC-SB, SB-SC and SB-SB. The translocation site in the chimeric chromosome is conserved among bottom-fermenting yeast strains, and was created by homologous recombination within a region of high sequence identity between the SC-type sequence and the SB-type sequence.


CONCLUSIONS
Existing bottom-fermenting yeast strains share a common ancestor in which the chimeric chromosome X was generated.


CONCLUSIONS
The knowledge gained in this study sheds light on the evolution of bottom-fermenting yeasts.
Ogata
T
T
Brewing Research & Development Laboratory, Asahi Breweries, Ltd, 1-1-21, Midori, Moriya, Ibaraki 302-0106, Japan. tomoo.ogata@asahibeer.co.jp
Izumikawa
M
M
Tadami
H
H
D000595:Amino Acid Sequence; D002678:Chimera; D002869:Chromosome Aberrations; D015825:Chromosomes, Fungal / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D006824:Hybridization, Genetic; D046228:Microarray Analysis; D016133:Polymerase Chain Reaction; D012440:Saccharomyces / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014178:Translocation, Genetic
D004271:DNA, Fungal