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The evolutionary origins and consequences of self-fertility in nematodes.

Ellis RE, Lin SY - F1000Prime Rep (2014)

Bottom Line: Self-fertile hermaphrodites have evolved from male/female ancestors in many nematode species, and this transition occurred on three independent occasions in the genus Caenorhabditis.Finally, the adoption of a hermaphroditic lifestyle had profound effects on ecological and sexual interactions and genomic organization.Thus, nematode mating systems are ideal for elucidating the origin of novel traits, and studying the influence of developmental processes on evolutionary change.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, Rowan University SOM, B303 Science Center 2 Medical Center Drive, Stratford, NJ 08084 USA.

ABSTRACT
Self-fertile hermaphrodites have evolved from male/female ancestors in many nematode species, and this transition occurred on three independent occasions in the genus Caenorhabditis. Genetic analyses in Caenorhabditis show that the origin of hermaphrodites required two types of changes: alterations to the sex-determination pathway that allowed otherwise female animals to make sperm during larval development, and the production of signals from the gonad that caused these sperm to activate and fertilize oocytes. Comparisons of C. elegans and C. briggsae hermaphrodites show that the ancestral sex-determination pathway has been altered in multiple unique ways. Some of these changes must have precipitated the production of sperm in XX animals, and others were modifying mutations that increased the efficiency of hermaphroditic reproduction. Reverse genetic experiments show that XX animals acquired the ability to activate sperm by co-opting one of the two redundant pathways that normally work in males. Finally, the adoption of a hermaphroditic lifestyle had profound effects on ecological and sexual interactions and genomic organization. Thus, nematode mating systems are ideal for elucidating the origin of novel traits, and studying the influence of developmental processes on evolutionary change.

No MeSH data available.


Related in: MedlinePlus

Self-fertile hermaphrodites are modified females that make and use spermA. Comparison of virgin female and hermaphrodite nematodes. Ventral up, anterior to the left. Oocytes are pink and sperm are blue. In the soma, the gonad is gray, the pharynx is light green, the intestine is dark green, the sex muscles are orange, the distal tip cells are yellow and the vulva purple.B. Male nematode. Primary spermatocytes are light blue hexagons, residual bodies are light blue circles, and spermatids are dark blue circles.
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fig-002: Self-fertile hermaphrodites are modified females that make and use spermA. Comparison of virgin female and hermaphrodite nematodes. Ventral up, anterior to the left. Oocytes are pink and sperm are blue. In the soma, the gonad is gray, the pharynx is light green, the intestine is dark green, the sex muscles are orange, the distal tip cells are yellow and the vulva purple.B. Male nematode. Primary spermatocytes are light blue hexagons, residual bodies are light blue circles, and spermatids are dark blue circles.

Mentions: Most nematode species have males and females, just like other animals. However, some species display a rare mating system known as androdioecy, which uses males and self-fertile hermaphrodites. In androdioecious nematodes, the XO animals are normal males but XX animals are hermaphrodites (Figure 2). These hermaphrodites look like females, but the first germ cells to differentiate become sperm, which are stored in the spermathecae and used later for self-fertilization. Subsequent germ cells become oocytes. Because hermaphrodites are anatomically female, they cannot mate with each other, but do produce cross progeny if mated with males.


The evolutionary origins and consequences of self-fertility in nematodes.

Ellis RE, Lin SY - F1000Prime Rep (2014)

Self-fertile hermaphrodites are modified females that make and use spermA. Comparison of virgin female and hermaphrodite nematodes. Ventral up, anterior to the left. Oocytes are pink and sperm are blue. In the soma, the gonad is gray, the pharynx is light green, the intestine is dark green, the sex muscles are orange, the distal tip cells are yellow and the vulva purple.B. Male nematode. Primary spermatocytes are light blue hexagons, residual bodies are light blue circles, and spermatids are dark blue circles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126538&req=5

fig-002: Self-fertile hermaphrodites are modified females that make and use spermA. Comparison of virgin female and hermaphrodite nematodes. Ventral up, anterior to the left. Oocytes are pink and sperm are blue. In the soma, the gonad is gray, the pharynx is light green, the intestine is dark green, the sex muscles are orange, the distal tip cells are yellow and the vulva purple.B. Male nematode. Primary spermatocytes are light blue hexagons, residual bodies are light blue circles, and spermatids are dark blue circles.
Mentions: Most nematode species have males and females, just like other animals. However, some species display a rare mating system known as androdioecy, which uses males and self-fertile hermaphrodites. In androdioecious nematodes, the XO animals are normal males but XX animals are hermaphrodites (Figure 2). These hermaphrodites look like females, but the first germ cells to differentiate become sperm, which are stored in the spermathecae and used later for self-fertilization. Subsequent germ cells become oocytes. Because hermaphrodites are anatomically female, they cannot mate with each other, but do produce cross progeny if mated with males.

Bottom Line: Self-fertile hermaphrodites have evolved from male/female ancestors in many nematode species, and this transition occurred on three independent occasions in the genus Caenorhabditis.Finally, the adoption of a hermaphroditic lifestyle had profound effects on ecological and sexual interactions and genomic organization.Thus, nematode mating systems are ideal for elucidating the origin of novel traits, and studying the influence of developmental processes on evolutionary change.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, Rowan University SOM, B303 Science Center 2 Medical Center Drive, Stratford, NJ 08084 USA.

ABSTRACT
Self-fertile hermaphrodites have evolved from male/female ancestors in many nematode species, and this transition occurred on three independent occasions in the genus Caenorhabditis. Genetic analyses in Caenorhabditis show that the origin of hermaphrodites required two types of changes: alterations to the sex-determination pathway that allowed otherwise female animals to make sperm during larval development, and the production of signals from the gonad that caused these sperm to activate and fertilize oocytes. Comparisons of C. elegans and C. briggsae hermaphrodites show that the ancestral sex-determination pathway has been altered in multiple unique ways. Some of these changes must have precipitated the production of sperm in XX animals, and others were modifying mutations that increased the efficiency of hermaphroditic reproduction. Reverse genetic experiments show that XX animals acquired the ability to activate sperm by co-opting one of the two redundant pathways that normally work in males. Finally, the adoption of a hermaphroditic lifestyle had profound effects on ecological and sexual interactions and genomic organization. Thus, nematode mating systems are ideal for elucidating the origin of novel traits, and studying the influence of developmental processes on evolutionary change.

No MeSH data available.


Related in: MedlinePlus