2022/02/18 by Ragib Ahsan, Wumei Blanche, Laura A. Katz · 2 citations
Biochemistry, Genetics and Molecular Biology · Environmental Science · #Genomics and Phylogenetic Studies #Microbial Community Ecology and Physiology #Protist diversity and phylogeny
paper · doi:10.1111/jeu.12898
openalex publication_date 2022/02/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Ciliates are defined by the presence of dimorphic nuclei as they have both a somatic macronucleus and germline micronucleus within each individual cell. The size and structure of both germline micronuclei and somatic macronuclei vary tremendously among ciliates. Except just after conjugation (i.e. the nuclear exchange in their life cycle), the germline micronucleus is transcriptionally inactive and contains canonical chromosomes that will be inherited between generations. In contrast, the transcriptionally active macronucleus contains chromosomes that vary in size in different classes of ciliates, with some lineages having extensively fragmented gene-sized somatic chromosomes while others contain longer multigene chromosomes. Here, we describe the variation in somatic macronuclear architecture in lineages sampled across the ciliate tree of life, specifically focusing on lineages with extensively fragmented chromosomes (e.g. the classes Phyllopharyngea and Spirotrichea). Further, we synthesize information from the literature on the development of ciliate macronuclei, focusing on changes in nuclear architecture throughout life cycles. These data highlight the tremendous diversity among ciliate nuclear cycles, extend our understanding of patterns of genome evolution, and provide insight into different germline and somatic nuclear features (e.g. nuclear structure and development) among eukaryotes.