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Sex- and Gamete-Specific Patterns of X Chromosome Segregation in a Trioecious Nematode.
- Source :
-
Current biology : CB [Curr Biol] 2018 Jan 08; Vol. 28 (1), pp. 93-99.e3. Date of Electronic Publication: 2017 Dec 21. - Publication Year :
- 2018
-
Abstract
- Three key steps in meiosis allow diploid organisms to produce haploid gametes: (1) homologous chromosomes (homologs) pair and undergo crossovers; (2) homologs segregate to opposite poles; and (3) sister chromatids segregate to opposite poles. The XX/XO sex determination system found in many nematodes [1] facilitates the study of meiosis because variation is easily recognized [2-4]. Here we show that meiotic segregation of X chromosomes in the trioecious nematode Auanema rhodensis [5] varies according to sex (hermaphrodite, female, or male) and type of gametogenesis (oogenesis or spermatogenesis). In this species, XO males exclusively produce X-bearing sperm [6, 7]. The unpaired X precociously separates into sister chromatids, which co-segregate with the autosome set to generate a functional haplo-X sperm. The other set of autosomes is discarded into a residual body. Here we explore the X chromosome behavior in female and hermaphrodite meioses. Whereas X chromosomes segregate following the canonical pattern during XX female oogenesis to yield haplo-X oocytes, during XX hermaphrodite oogenesis they segregate to the first polar body to yield nullo-X oocytes. Thus, crosses between XX hermaphrodites and males yield exclusively male progeny. During hermaphrodite spermatogenesis, the sister chromatids of the X chromosomes separate during meiosis I, and homologous X chromatids segregate to the functional sperm to create diplo-X sperm. Given these intra-species, intra-individual, and intra-gametogenesis variations in the meiotic program, A. rhodensis is an ideal model for studying the plasticity of meiosis and how it can be modulated.<br /> (Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
Details
- Language :
- English
- ISSN :
- 1879-0445
- Volume :
- 28
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Current biology : CB
- Publication Type :
- Academic Journal
- Accession number :
- 29276124
- Full Text :
- https://doi.org/10.1016/j.cub.2017.11.037