Document Type

Article

Publication Date

10-1-2017

Publication Title

European Journal of Protistology

Abstract

Genome structure and nuclear organization have been intensely studied in model ciliates such as Tetrahymena and Paramecium, yet few studies have focused on nuclear features of other ciliate clades including the class Karyorelictea. In most ciliates, both the somatic macronuclei and germline micronuclei divide during cell division and macronuclear development only occurs after conjugation. However, the macronuclei of Karyorelictea are non-dividing (i.e. division minus (Div−)) and develop anew from micronuclei during each asexual division. As macronuclei age within Karyorelictea, they undergo changes in morphology and DNA content until they are eventually degraded and replaced by newly developed macronuclei. No less than two macronuclei and one micronucleus are present in karyorelictid species, which suggests that a mature macronucleus 1) might be needed to sustain the cell while a new macronucleus is developing and 2) likely plays a role in guiding the development of the new macronucleus. Here we use a phylogenetic framework to compile information on the morphology and development of nuclei in Karyorelictea, largely relying on the work of Dr. Igor Raikov (1932–1998). We synthesize data to speculate on the functional implications of key features of Karyorelictea including the presence of at least two macronuclei in each cell and the inability for macronuclei to divide.

Keywords

Karyorelictea, Non-dividing macronuclei, Nuclear architecture

Volume

61

First Page

399

Last Page

408

DOI

10.1016/j.ejop.2017.05.002

ISSN

09324739

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Rights

Licensed to Smith College and distributed CC-BY under the Smith College Faculty Open Access Policy.

Comments

Peer reviewed accepted manuscript.

Included in

Biology Commons

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