Janet Devitis Kolesar, Boynton-Gillham laboratory, Duke University

Phenotype: chlorophyll b deficient

The cd (chlorophyll-deficient) mutants were described in a master’s thesis at Duke University by Janet Devitis Kolesar in the Boynton-Gillham laboratory. They are deficient in chlorophyll a/b, mostly b.

Janet Devitis Kolesar, Boynton-Gillham laboratory, Duke University

Phenotype: chlorophyll b deficient

The cd (chlorophyll-deficient) mutants were described in a master’s thesis at Duke University by Janet Devitis Kolesar in the Boynton-Gillham laboratory. They are deficient in chlorophyll a/b, mostly b.

From Lawrence Bogorad to Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (erythromycin)

This is a good chloroplast marker for erythromycin resistance, and has been used in many crosses. It maps to the 3′ end of the 23S rRNA gene, distal to the intron, and is a C-> T base change in the 23S rRNA at the position equivalent to E. coli 2611.


Mets LJ and Bogorad L (1971) Mendelian and uniparental alterations in erythromycin binding by plastid ribosomes. Science 174:707-709

Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnL
  • Chromosome:
  • chloroplast

Karen VanWinkle-Swift, Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (erythromycin)

Isolated by Karen VanWinkle-Swift. This is her original isolate.
This is a good chloroplast marker for erythromycin resistance, and has been used in many crosses. It maps to the center of the 23S rRNA gene, proximal to the intron, and is a G -> A base change in the 23S rRNA at the position equivalent to E. coli 2057.


Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnL
  • Chromosome:
  • chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (erythromycin)

The ery10 mutant is an ery1 allele that was isolated in the Boynton-Gillham laboratory in 1969 following mutagenesis with nitrosoguanidine. This strain is a product from the cross of the original mutant that demonstrated that it showed Mendelian inheritance.

This strain grows on 100 micrograms/ml erythromycin on HS minimal medium but crashes on 250 micrograms/ml erythromycin on HSHA acetate medium 8/86.

For more information on the ERY1 locus, please see CC-504.


  • Locus:
  • ERY1 [PRPL4]
  • Chromosome:
  • 11

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (erythromycin)

The ery11 mutant is an ery1 allele that was isolated in the Boynton-Gillham laboratory in 1969 following mutagenesis with nitrosoguanidine. This strain is a product from the cross of the original mutant that demonstrated that it showed Mendelian inheritance.

For more information on the ERY1 locus, please see CC-504.


  • Locus:
  • ERY1 [PRPL4]
  • Chromosome:
  • 11

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (erythromycin)

The ery3a mutation was obtained in the Boynton/Gillham laboratory, induced by mutagenesis with nitrosoguanidine and shown to be equivalent to ery-2y in Surzycki and Gillham (1971) and papers by Chiang and colleagues.

This is a very useful strain for mapping on the right arm of linkage group I, easy to score as resistant to 100 micrograms/ml erythromycin on minimal medium.

We suspect the ERY3 locus corresponds to the PRPL34 gene, encoding chloroplast ribosomal protein L34.


Surzycki SJ and Gillham NW (1971) Organelle mutations and their expression in Chlamydomonas reinhardi. Proc. Natl Acad Sci USA 68:1301-1306

Davidson JN, Hanson MR, Bogorad L (1978) Erythromycin resistance and the chloroplast ribosome in Chlamydomonas reinhardi. Genetics 89:281-297


  • Locus:
  • ERY3
  • Chromosome:
  • 1

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (erythromycin)

The ery14 mutant is an allele at the ERY1 locus. This strain grows well on 100 micrograms/ml erythromycin on minimal medium.

For more information on the ERY1 locus, please see CC-504.


  • Locus:
  • ERY1 [PRPL4]
  • Chromosome:
  • 11

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (erythromycin)

This strain was derived in the Boynton-Gillham laboratory from a cross of a strain originally identified as ery21. This is a very useful strain for mapping on the right arm of linkage group I, easy to score as resistant to 100 micrograms/ml erythromycin on minimal medium.

For more information on the ERY3 locus, please see CC-73.


  • Locus:
  • ERY3
  • Chromosome:
  • 1

Boynton-Gillham laboratory, Duke University

Phenotype: requires nicotinamide

From R.P. Levine, brought to Duke by Gillham in 1968. The nic7 mutant is easily scored by sensitivity to 3-acetyl pyridine. This is a mutation in the gene encoding quinolinate synthetase.


Ferris PJ (1995) Localization of the nic-7, ac-29 and thi-10 genes within the mating-type locus of Chlamydomonas reinhardtii. Genetics 141:543-549


  • Locus:
  • NIC7 [QSA1]
  • Chromosome:
  • 6

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (kanamycin or neamine)

Product from a cross of wild type mt+ (N.W. Gillham’s strain, equivalent to CC-125) to nr-u-2-1 sr-u-2-60 mt-.

This is a useful chloroplast marker, mapping to the 3′ end of the chloroplast 16S ribosomal RNA. The mutation is an A>G change at nucleotide 1340. Although isolated initially as a neamine-resistant strain, it is also resistant to kanamycin, a more readily available antibiotic. CC-86 was used in many crosses in the Boynton-Gillham laboratory in the 1970s.


Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnS
  • Chromosome:
  • chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (kanamycin or neamine)

Product from a cross of CC-86 nr-u-2-1 mt+ x arg2 mt-. This stock is not arginine-requiring.

This is a useful chloroplast marker, mapping to the 3′ end of the chloroplast 16S ribosomal RNA. The mutation is an A>G change at nucleotide 1340. Although isolated initially as a neamine-resistant strain, it is also resistant to kanamycin, a more readily available antibiotic.


Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnS
  • Chromosome:
  • chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (paromomycin)

This is a spontaneous mutant isolated by N.W. Gillham prior to 1968, and is resistant to 10 micrograms/ml paromomycin. CC-89 was obtained from a cross of the original mutant. This is a nuclear mutation, defining a locus on linkage group X, and is a useful genetic marker.

Karen VanWinkle-Swift (unpublished) and Geraldine Fleming (Ph.D. thesis, Duke University) obtained viomycin-resistant mutants that proved to be alleles at this locus.


Gillham NW (1965) Induction of chromosomal and nonchromosomal mutations in Chlamydomonas reinhardi with N-methyl-N'-nitro-N-nitrosoguanidine. Genetics 52:529-537


  • Locus:
  • PR1
  • Chromosome:
  • 10

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (paromomycin)

Isolated by N.W. Gillham prior to 1968, resistant to 10 micrograms/ml paromomycin. CC-90 was obtained from a cross of the original mutant.

Please see CC-89 for more information on the PR1 locus.


  • Locus:
  • PR1
  • Chromosome:
  • 10

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (streptomycin)

This is a haploid derivative of the original sr-u-sm-3a strain, which was a diploid. The streptomycin resistance results from a mutation in the gene encoding chloroplast 16S rRNA. This mutation is unique among chloroplast sr mutants examined in having an alteration in the extreme 5′ end of the 16S rRNA molecule (U -> G at nt 14, corresponding to E. coli 13)


Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnS
  • Chromosome:
  • chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (spectinomycin)

CC-104 was derived from a cross of CC-105 spr-u-1-27-3 mt+ to an ac20 cr1 strain. A tetratype tetrad was selected; this is the product that carries the wild type alleles of the ac20 and cr1 mutations.

Because this strain was used frequently in chloroplast genetics studies in the Boynton-Gillham laboratory, it was chosen from among several spr-u-1-27-3 strains as the representative mt+ stock for that mutation in the core collection.

spr-u-1-27-3 is a G -> A mutation at bp 1125 in the chloroplast 16S rRNA gene, and confers relatively low levels of spectinomycin resistance. Cells of this mutant grown on minimal medium on agar are killed by 100 micrograms/ml spectinomycin but will grow on acetate at this concentration.


Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnS
  • Chromosome:
  • chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (spectinomycin)

This strain was derived at Duke from a cross between CC-147 nr1-8 spr-u-1-62 and CC-198 er-u-37 sr-u-2-60; it does not carry nr1-8 or the markers from CC-198.

This is a good chloroplast resistance marker, easy to score on 100 microgram/ml spectinomycin. spr-u-1-6-2 is an A to G mutation at position 1123 in the chloroplast 16S rRNA and confers high level spectinomycin resistance under all growth conditions.


Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnS
  • Chromosome:
  • chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (streptomycin)

Originally from R.P. Levine, designated sr-1-H-5; this stock is a derivative of the mutant strain originally isolated by N.W. Gillham in Levine’s laboratory and was designated sr-1a. Although alleles at the SR1 locus are readily obtained, and are mentioned in papers by Sager and others, we think the sr1 mutation in the various multiply marked strains in our collection is probably this one.

This is an excellent marker for linkage group IX, easy to score as resistant to 100 micrograms/ml streptomycin. In contrast to some chloroplast-encoded streptomycin-resistant mutants, sr1 is not resistant to 500 micrograms/ml streptomcin.

Bartlett et al. showed that this mutation confers resistance directly on the small subunit of the chloroplast ribosome. Based on its map position and analogous mutations in bacteria, we suspect that the SR1 locus may correspond to the PRPS17 gene, encoding protein S17 of the chloroplast ribosome.


Sager R (1955) Inheritance in the Green Alga Chlamydomonas Reinhardi. Genetics 40:476-489

Gillham NW and Levine RP (1962a) Studies on the origin of streptomycin resistant mutants in Chlamydomonas reinhardi. Genetics 47:1463-1474

Bartlett SG, Harris EH, Grabowy CT, Gillham NW, Boynton JE (1979) Ribosomal subunits affected by antibiotic resistance mutations at seven chloroplast loci in Chlamydomonas reinhardtii. Mol Gen Genet 176:199-208


  • Locus:
  • SR1
  • Chromosome:
  • 9

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (streptomycin)

Originally from R.P. Levine, = his ‘clone 1′
This stock is a derivative of the mutant strain originally isolated by N.W. Gillham in Levine’s laboratory and designated sr-1a.

Please see CC-112 for more information on this mutation.


  • Locus:
  • SR1
  • Chromosome:
  • 9

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (streptomycin)

CC-118 was derived from a cross of wild type mt+ x sr-u-2-60 mt- (equivalent to CC-119).

This is an excellent chloroplast mutant, easy to score as resistant to up to 500 micrograms/ml streptomycin on agar (50-100 micrograms is sufficient to kill wild type cells). The mutation is an A to C change at base 474 of 16S rRNA gene (equivalent to E. coli 523).


Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnS
  • Chromosome:
  • chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (streptomycin)

This is the original sr-u-2-60 mutant isolated by N.W. Gillham.
This is an excellent chloroplast mutant, easy to score as resistant to up to 500 micrograms/ml streptomycin on agar (50-100 micrograms is sufficient to kill wild type cells). The mutation is an A to C change at base 474 of 16S rRNA gene (equivalent to E. coli 523).


Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnS
  • Chromosome:
  • chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic and inhibitor resistant (canavainine, methionine sulfoximine, streptomycin)

An early strain, derived from a cross by Gillham.
This is a potentially useful combination of three easily scored markers for comparison of Mendelian vs. uniparental inheritance.


  • Locus:
  • CAN1, MSR1, rrnS
  • Chromosome:
  • 1,7,chloroplast

Boynton-Gillham laboratory, Duke University; originally from R.P. Levine.

Phenotype: requires thiamine

This strain shows slow growth on minimal medium. This mutation is in the gene encoding hydroxyethylthiazole kinase, a protein in the thiamine biosynthesis pathway. The locus is within the mating type region on chromosome 6.


Ferris PJ (1995) Localization of the nic-7, ac-29 and thi-10 genes within the mating-type locus of Chlamydomonas reinhardtii. Genetics 141:543-549


  • Locus:
  • THI10
  • Chromosome:
  • 6

Boynton-Gillham laboratory, Duke University

This is the basic “137c” wild type strain originally from G.M. Smith, isolated in 1945 near Amherst MA, and is presumably equivalent to strain 11/32d of the Culture Centre of Algae and Protozoa. This particular strain was brought to Duke by N.W. Gillham in 1968 from R.P. Levine’s laboratory at Harvard.

CC-124 and CC-125 carry the nit1 and nit2 mutations, and cannot grow on nitrate as their sole N source. CC-124 carries the agg1 allele for phototactic aggregation (see CC-1328 for more information), in contrast to CC-125, which has the agg1+ allele at this locus.

For more information on the origin of the standard laboratory strains of C. reinhardtii, please see the following paper:


Pröschold T, Harris EH, Coleman AW (2005) Portrait of a species: Chlamydomonas reinhardtii. Genetics 170:1601-1610


  • Locus:
  • AGG1
  • Chromosome:
  • 13

Boynton-Gillham laboratory, Duke University

This is the basic “137c” wild type strain originally from G.M. Smith, isolated in 1945 near Amherst MA, and is presumably equivalent to strain 11/32c of the Culture Centre of Algae and Protozoa. This particular strain was brought to Duke by N.W. Gillham in 1968 from R.P. Levine’s laboratory at Harvard.

CC-124 and CC-125 carry the nit1 and nit2 mutations, and cannot grow on nitrate as their sole N source. CC-125 carries the AGG1 (agg1+) allele for phototactic aggregation, in contrast to CC-124, which has the agg1 allele at this locus.

CC-125 is the background strain for many mutations, including CC-503 cw92 mt+ which was the source of DNA used for genomic sequencing.

For more information on the origin of the standard laboratory strains of C. reinhardtii, please see the following paper:


Pröschold T, Harris EH, Coleman AW (2005) Portrait of a species: Chlamydomonas reinhardtii. Genetics 170:1601-1610

Boynton-Gillham laboratory, Duke University

From a cross in R.P. Levine’s laboratory of arg2 mt+ x arg7 mt, selected as a potential diploid. This strain was brought to Duke by N.W. Gillham in 1968. Arginine-requiring progeny have been recovered from crosses to wild type mt+.

This is the strain we normally distribute when a basic “wild type” diploid strain is requested. Karen Kindle has reported that CC-127 grows on nitrate, suggesting (somewhat to our surprise) that at least one of the parental stocks was not in the Levine (nit1 nit2) 137c background.


Ebersold WT (1967) Chlamydomonas reinhardi: heterozygous diploid strains. Science 157:447-449

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (erythromycin, kanamycin/neamine, spectinomycin)

Isolated at Duke from a spontaneous biparental zygote in a cross of GB-140 (nr-u-2-1 spr-u-1-H-4 sr-u-2-60) to CC-67 (er-u-37), and used in chloroplast mapping crosses..

Caution! This is NOT the same thing as “wild type strain 137c”. If that’s what you’re looking for, see CC-124 and CC-125.


  • Locus:
  • rrnL, rrnS
  • Chromosome:
  • chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (neamine, spectinomycin)

From a cross by Gillham of spr-u-1-6-2 mt+ x nr-u-2-1 sr-u-2-60 mt-, selected as a potential recombinant resistant to both spectinomycin and nearmine, but sensitive to streptomycin.

When outcrossed to wild type, the neamine resistance in this strain showed Mendelian segregation, and the strain was not cross-resistant to kanamycin (although the original nr-u-2-1 mutant is resistant) nor were chloroplast ribosomes resistant to neamine in poly-U directed amino acid incorporation. Therefore this strain contains a new spontaneous neamine-resistance mutation. Subsequently this was mapped to linkage group VIII and shown to be allelic with other nuclear nr1 mutants. This particular allele was designated nr1-1, and is the allele present in a number of derivative strains, including CC-975, CC-1088, CC-1144, CC-1714, CC-1720, CC-1730, CC-1735, and probably CC-2645.

This is a good strain to use either for spr-u-1-6-2 or nr1 in mt-.


  • Locus:
  • NR1, rrnS
  • Chromosome:
  • 8,chloroplast

Boynton-Gillham laboratory, Duke University

Phenotype: requires acetate; cold sensitive on minimal medium

Product 5.6.2 from a cross of wild type to the original ac20 cr1 double mutant (CC-154 mt-, a strain now discontinued.)

This strain was used by Boynton et al. (1972) in their study of mutants deficient in chloroplast ribosomes. This strain is a good choice when maximal deficiency in chloroplast protein synthesis is desired. Even so, this strain does not have a stringent acetate requirement, and does grow slightly on minimal medium. Scoring is easier at cool temperatures, e.g. 15 degrees.


Boynton JE, Gillham NW, Burkholder B (1970) Mutations Altering Chloroplast Ribosome Phenotype in Chlamydomonas, II. A New Mendelian Mutation. Proc Natl Acad Sci USA 67:1505-1512

Boynton JE, Gillham NW, Chabot JF (1972) Chloroplast ribosome deficient mutants in the green alga Chlamydomonas reinhardi and the question of chloroplast ribosome function. J Cell Sci 10:267-305


  • Locus:
  • AC20, CR1
  • Chromosome:
  • 1,12

Boynton-Gillham laboratory, Duke University

Phenotype: antibiotic resistant (streptomycin)

This is a subclone of the original sr-u-2-23 mutant, which was induced in the Boynton-Gillham lab at Duke, using nitrosoguanidine as mutagen.

This strain shows moderately low levels of streptomycin resistance (50-100 micrograms/ml) on minimal medium, and somewhat higher levels of resistance when grown on acetate. The mutation is a C>U change at position 856 in the chloroplast 16S rRNA, equivalent to position 912 of E. coli


Conde MF, Boynton JE, Gillham NW, Harris EH, Tingle CL, Wang WL (1975) Chloroplast genes in Chlamydomonas affecting organelle ribosomes. Genetic and biochemical analysis of antibiotic-resistant mutants at several gene loci. Mol Gen Genet 140:183-220

Harris EH, Burkhart BD, Gillham NW, Boynton JE (1989) Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome. Genetics 123:281-292


  • Locus:
  • rrnS
  • Chromosome:
  • chloroplast