Scientists have found evidence that Giardia, an ancient protist long considered to be asexual, may have a sex life. John Logsdon and colleagues at the University of Iowa found that the protist has homologs of crucial meiotic proteins.1

Logsdon's team ran BLAST searches on the nearly complete Giardia lamblia genome project and detected homologs of five meiosis-specific genes found in plants, animals, and fungi: Dmc1 promotes interhomolog recombination; Spo11 creates DNA double-strand breaks; Hop1 is part of the synaptonemal complex; and Hop2 and Mnd1 ensure accurate and efficient homology searching. The researchers say these meiosis-specific genes, in conjunction with the presence of known meiosis-related genes, provide strong evidence that the protist has or very recently had the capacity for sexual reproduction.

"What I would like to know in further studies is if the presence of these genes indicates meiotic sex or premeiotic parasex, in which many of the...

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