Giant viruses emerge as persistent residents of aquatic fungi
PLOS Biology reports a newly named giant-virus clade that can persist in aquatic fungi, sometimes integrating into host genomes. Elsewhere, a reconstructed banana-family ancestor starts with 17 chromosomes before later fusions, while exome sequencing found genetic explanations in 12 per cent of a small Estonian group with unexplained premature ovarian insufficiency.
Science··Midday
Mycodnaviridae can persist quietly in fungi
Mycodnaviridae, described in PLOS Biology, is a newly named clade of giant viruses that persistently infect zoosporic aquatic fungi. A scan of 141 fungal genomes found giant-virus capsid traces in 17; among Allomyces isolates, the capsid gene appeared in 30 of 58, or 51.7 per cent. Viral assemblies reach 350 kilobases and carry more than 300 genes. Some sequences are integrated into host genomes while other viruses actively replicate, and what switches a quiet infection into an active one remains unknown.[1]
The banana family's chromosome history starts at 17
Researchers comparing the Musa exotica genome with other sequenced members of the banana family reconstructed an ancestral set of 17 chromosomes. Translocations and fusions then reduced that number step by step to the 9 to 11 chromosomes seen in living species. The Current Biology study also links rearrangements to bract colour through anthocyanin genes. The team says the reconstruction can help track genetic material retained by wild relatives of cultivated bananas, which rest on a narrow genetic base.[2]
Exome testing explains 12 per cent of unresolved cases
The team at University of Tartu read protein-coding regions in cases of premature ovarian insufficiency with no known cause and found a genetic explanation in 12 per cent. The results covered both single-gene variants and larger chromosomal changes. Looking for different kinds of change in one analysis can give families information about inherited risk and fertility planning. Because the group was small and drawn from one country, 12 per cent is an initial estimate rather than an established rate for other populations.[3]
