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Rapid ID of yeasts by gene sequences
• Domains 1 and 2 (D1/D2) of LSU rDNA
•Easy to PCR (universal primers), sequence, align…
•Short (400-650 bp) but variable enough to
distinguish most of yeast species
•Universally available database for all known yeast species
Kurtzman and Robnett (1998) - ascomycete yeasts
Fell et al. (2000) - basidiomycete yeasts
Correlation of nDNA relatedness and D1/D2 sequence
divergence among ascomycetous yeasts
Strain pairs
% nDNA
relatedness
D1/D2 nucleotide
differences
Conspecific
>70%
0-3
Unrelated
<20%
6-250
Kurtzman 2006, Mycoscience 47: 65-71
1927 yeast strains from insect guts
D1/D2 sequencing
Database
686 strains - Known yeasts
81 ascomycetous spp.
39 basidiomycetous spp.
1241 strains - New yeasts
214 ascomycete spp.
31 basidiomycete spp.
18S, ITS,
phenotypic characters
618 strains - Described
as 66 novel ascomycete spp.
Is single gene enough for ID?
B
A
C
Quic k Ti me™ and a
T IFF (Unc om pres s ed) dec om pres s or
are needed to s ee t his pic t ure.
Other genes
•ITS - widely, useful for closely related taxa
•cytochrome oxidase II - Belloch et al. 2000
•actin-1 - Daniel et al. 2001
•EF1-a, RPB II, mSSU - Kurtzman & Robnett 2003, 2007