Table 5.

Identification of known meiosis-specific genes used as a meiosis detection toolkit

Species	Meiosis-specific genesa
	Spo11-2	Mer3	Hop1	Dmc1	Hop2	Mnd1	Msh4	Msh5
Saccharomyces cerevisiae	X	X	X	X	X	X	X	X
Chlamydomonas reinhardtii	X	X	X	X	X	X	X	X
Volvox carteri	X	X	X	X	X	X	X	X
Ectocarpus siliculosus	X	X	X	X	X	X	X	X
Emiliania huxleyi	X	X	X	X	X	X	X	X
Nannochloropsis oceanica	X	X	−	−	X	−	X	X
N. gaditana	X	X	−	X	−	X	X	X

^aOf nine meiosis-specific genes^{51, 52}, Rec8 is not identified in two species of genus Nannochloropsis. A homologous gene of Rec8 is found in the genome of N. oceanica; however, it is phylogenetically similar to Rad21, a meiosis associating gene. We believed that a meiosis-specific gene is truly absent and not replaced by an unidentified gene if it exists in a wide taxonomical range of species which include here, for example, a yeast, two green algae, a brown alga, and a haptophyte. These genes are identified by searching against the genomes either downloaded from public databanks or sequenced ourselves (N. oceanica) with BLASTp or tBLASTn and by phylogenetic analysis