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Table 1 Functional roles of meiotic genes searched in the diatom genomes

From: Identification of the meiotic toolkit in diatoms and exploration of meiosis-specific SPO11 and RAD51 homologs in the sexual species Pseudo-nitzschia multistriata and Seminavis robusta


Role in meiosis

DNA replication and chromosome maintenance


Mcm2-7 form hexamer and are involved in DNA replication [28]


Mcm8 and Mcm9 are involved in meiotic recombination [81, 83, 84]


Mcm8 and Mcm9 are involved in meiotic recombination [83, 84]


Part of sister chromatids cohesin subunit, act as a heterodimer


Heterodimer, essential for chromosome assembly and segregation, part of core condensing subunits


Heterodimer, involved in DNA repair and checkpoint response, binds to single stranded DNA (ssDNA)


Involved in maintenance of sister chromatid cohesion in late prophase


Interacts with cohesin complex Smc1-Smc3 and Rad21/Rec8 and helps in holding cohesin ring together


Meiotic homolog of Rad21, involved in holding sister chromatids together during meiotic recombination


Holds Smc1 and Smc3 together thus holding sister chromatids together during meiosis and mitosis

DNA double strand break formation


Creates double strand breaks (DSBs) in homologous chromosomes in meiotic recombination


Creates DSBs in homologous chromosomes in meiotic recombination in plants

 Spo11-3/Top VIA

Required for endoreduplication of DNA

DNA damage sensing and response


DNA binding ATPase, holds broken DNA strands while Mre11 trims DSBs


3′–5′ dsDNA exonuclease and ssDNA endonuclease; trims 

broken DNA ends after DSBs and hairpins


Component of Mre11-Rad50-Xrs2, involved in homologous recombination and non-homologous end joining [125]

Crossover regulation


DNA helicase that unwinds double stranded DNA during meiotic cross over formation [126]


Binds to DSBs, component of lateral and axial synaptonemal complex


Component of synaptonemal complex, interacts with Hop1 and facilitates meiosis I chromosome disjunction [48, 49]


Transverse filament protein involved in synaptonemal complex formation during meiosis [45, 47]



Components of synaptonemal complex required for morphogenesis of the synaptonemal complex [45, 64]


Meiotic member of Rad51-RadA-RecA superfamily of proteins, binds to ssDNA end of DSBs and is involved in inter-homologous recombination


Homology search together with Mnd1, works in Dmc1 dependent homology search pathway downstream of Rad51


Together with Hop2 works in homology searching and is also required in stable DNA heteroduplex


Heterodimer, together with Mlh1/Mhl3 heterodimer directs Holliday junction resolution with crossover interference

Double-strand break repair (recombinational repair)

 Rad51, Xrcc2, Xrcc3

Mediate homologous pairing and strand invasion, involved in DNA repair mechanisms in mitosis and meiosis. Part of Rad51-RadA-RecA superfamily, exhibit multiple paralogs


Binds to ssDNA and initiates homologous recombination, stimulates Rad51 mediated strand invasion


5′-3′ endonuclease, required in meiotic crossing over, functions during nucleotide excision repair


Forms heterodimer with Msh3 or Msh6, works in DNA mismatch repair


Forms heterodimer with Msh2, works in DNA mismatch repair


DNA mismatch repair protein, forms heterodimers with Mlh2, Mlh3 and Pms1, interacts with Msh2/Msh6 and Msh4/Msh5


DNA mismatch repair protein, forms heterodimer with Mlh1


Forms heterodimer with Mlh1, interacts with Msh4/Msh5 to promote meiotic crossovers


Forms heterodimer with Mlh1, involved in DNA mismatch repair


Interacts with Mus81 and is involved in interference insensitive, class II crossovers during meiotic recombination [104]


Interacts with Mms4 and is involved in interference insensitive, class II crossovers during meiotic recombination [104]


DNA helicase required for genome stability, involved in limiting meiotic crossovers [127]

Other accessory proteins required during meiosis


Fen1 functions during homologous recombination mediated DNA repair by removing divergent sequences at DNA break ends [128]


A double-stranded DNA-specific 5′–3′ exonuclease [129]


A conserved DNA nuclease involved in DNA stability [130]


Regulates meiotic spindle assembly [131]


Involved in DNA damage-induced Rad51 foci formation during meiosis [132]

  1. Gene functions are taken from Malik et al. [6] and from Hanson et al. [33] unless otherwise mentioned. Genes marked with a are considered meiosis-specific genes and do not have known functions outside of meiosis