A Bias Caused by Ectopic Development Produces Sexually Dimorphic Sperm in Nematodes

Baldi, Christopher; Viviano, Jeffrey; Ellis, Ronald

doi:10.1016/j.cub.2011.07.034

Cited by 21 publications

(37 citation statements)

References 48 publications

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“…Large size plays an important role in nematode sperm competition (LaMunyon and Ward, , ). Consistent with this observation, male sperm are smaller in androdioecious species than in gonochoristic ones (LaMunyon and Ward, ; Baldi et al, ). Furthermore, they are less likely to harm mates than sperm from gonochoristic males (Ting et al, ).…”

Section: The Effects Of Self‐fertility On Other Sexual Traitsmentioning

confidence: 55%

“…In androdioecious species, hermaphrodites make smaller sperm than males (LaMunyon and Ward, ). Although selection favors this trait (LaMunyon and Ward, , ), it is largely due to development of sperm in a female body and occurs even when female animals are artificially induced to make sperm (Baldi et al, ).…”

Section: The Effects Of Self‐fertility On Other Sexual Traitsmentioning

confidence: 99%

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“The persistence of memory”—Hermaphroditism in nematodes

Ellis

2016

Molecular Reproduction Devel

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SUMMARYSelf-fertility has evolved many times in nematodes. This transition often produces an androdioecious species, with XX hermaphrodites and XO males. Although these hermaphrodites resemble females in most respects, early germ cells differentiate as sperm, and late ones as oocytes. The sperm then receive an activation signal, populate the spermathecae, and are stored for later use in self-fertilization. These traits are controlled by complex modifications to the sex-determination and sperm activation pathways, which have arisen independently during the evolution of each hermaphroditic species. This transformation in reproductive strategy then promotes other major changes in the development, evolution, and population structure of these animals.Mol. Reprod. Dev. 84: 144À157, 2017. ß 2016 Wiley Periodicals, Inc. The unique requirements that self-fertility places on the sexdetermination process in nematodes provide a window into the complex interactions between developmental and evolutionary forces.

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Section: The Effects Of Self‐fertility On Other Sexual Traitsmentioning

confidence: 55%

Section: The Effects Of Self‐fertility On Other Sexual Traitsmentioning

confidence: 99%

“The persistence of memory”—Hermaphroditism in nematodes

Ellis

2016

Molecular Reproduction Devel

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“…As the spe-8 group of genes predated the origin of self-fertility, we wondered if the similarity between C. elegans and C. briggsae was caused by chance or a developmental bias 29 that favoured the use of these genes in hermaphrodites. Thus, we examined a third androdioecious species-C. tropicalis (formerly sp.…”

Section: Resultsmentioning

confidence: 99%

“…More importantly, we found that two different sperm activation programs can be co-opted for this purpose. Usually, developmental biases or constraints are thought to prevent certain types of variation from occurring, which prevents some evolutionary transitions 29 . Our results imply that some patterns of developmental regulation favour certain types of change, as the existence of two sperm activation pathways in nematodes helps explain why self-fertility has originated so frequently in this group 8 .…”

Section: Discussionmentioning

confidence: 99%

Co-option of alternate sperm activation programs in the evolution of self-fertile nematodes

et al. 2014

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Self-fertility evolved independently in three species of Caenorhabditis, yet the underlying genetic changes remain unclear. This transition required that XX animals acquire the ability to produce sperm and then signal those sperm to activate and fertilise oocytes. Here, we show that all genes that regulate sperm activation in C. elegans are conserved throughout the genus, even in male/female species. By using gene editing, we show that C. elegans and C. briggsae hermaphrodites use the SPE-8 tyrosine kinase pathway to activate sperm, whereas C. tropicalis hermaphrodites use a TRY-5 serine protease pathway. Finally, our analysis of double mutants shows that these pathways were redundant in ancestral males. Thus, newly evolving hermaphrodites became self-fertile by co-opting either of the two redundant male programs. The existence of these alternatives helps explain the frequent origin of self-fertility in nematode lineages. This work also demonstrates that the new genome-editing techniques allow unprecedented power and precision in evolutionary studies.

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“…Indeed, the presence of smaller sperm in hermaphrodites seems to have been originally caused by a developmental bias, rather than selection [173]. If females from a male/female species are induced to produce sperm by manipulating the sex determination pathway, these sperm are smaller than those from their male counterparts.…”

Section: Germline Warfarementioning

confidence: 99%

The regulation of spermatogenesis and sperm function in nematodes

Ellis

Stanfield

2014

Seminars in Cell & Developmental Biology

110

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In the nematode C. elegans, both males and self-fertile hermaphrodites produce sperm. As a result, researchers have been able to use a broad range of genetic and genomic techniques to dissect all aspects of sperm development and function. Their results show that the early stages of spermatogenesis are controlled by transcriptional and translational processes, but later stages are dominated by protein kinases and phosphatases. Once spermatids are produced, they participate in many interactions with other cells — signals from the somatic gonad determine when sperm activate and begin to crawl, signals from the female reproductive tissues guide the sperm, and signals from sperm stimulate oocytes to mature and be ovulated. The sperm also show strong competitive interactions with other sperm and oocytes. Some of the molecules that mediate these processes have conserved functions in animal sperm, others are conserved proteins that have been adapted for new roles in nematode sperm, and some are novel proteins that provide insights into evolutionary change. The advent of new techniques should keep this system on the cutting edge of research in cellular and reproductive biology.

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A Bias Caused by Ectopic Development Produces Sexually Dimorphic Sperm in Nematodes

Cited by 21 publications

References 48 publications

“The persistence of memory”—Hermaphroditism in nematodes

“The persistence of memory”—Hermaphroditism in nematodes

Co-option of alternate sperm activation programs in the evolution of self-fertile nematodes

The regulation of spermatogenesis and sperm function in nematodes

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