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Mating type in Chlamydomonas is specified by mid, the minus-dominance gene.

ABSTRACT: Diploid cells of Chlamydomonas reinhardtii that are heterozygous at the mating-type locus (mt+/mt-) differentiate as minus gametes, a phenomenon known as minus dominance. We report the cloning and characterization of a gene that is necessary and sufficient to exert this minus dominance over the plus differentiation program. The gene, called mid, is located in the rearranged (R) domain of the mt- locus, and has duplicated and transposed to an autosome in a laboratory strain. The imp11 mt- mutant, which differentiates as a fusion-incompetent plus gamete, carries a point mutation in mid. Like the fus1 gene in the mt+ locus, mid displays low codon bias compared with other nuclear genes. The mid sequence carries a putative leucine zipper motif, suggesting that it functions as a transcription factor to switch on the minus program and switch off the plus program of gametic differentiation. This is the first sex-determination gene to be characterized in a green organism.

SUBMITTER: Ferris PJ

PROVIDER: S-EPMC1208056 | biostudies-other | 1997 Jul

REPOSITORIES: biostudies-other

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Mating type in Chlamydomonas is specified by mid, the minus-dominance gene.

Ferris P J PJ Goodenough U W UW

Genetics 19970701 3

Diploid cells of Chlamydomonas reinhardtii that are heterozygous at the mating-type locus (mt+/mt-) differentiate as minus gametes, a phenomenon known as minus dominance. We report the cloning and characterization of a gene that is necessary and sufficient to exert this minus dominance over the plus differentiation program. The gene, called mid, is located in the rearranged (R) domain of the mt- locus, and has duplicated and transposed to an autosome in a laboratory strain. The imp11 mt- mutant, ...[more]

PMID: 9215892

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Gametogenesis in the Chlamydomonas reinhardtii minus mating type is controlled by two genes, MID and MTD1.

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