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Experimental insight into the proximate causes of male persistence variation among two strains of the androdioecious Caenorhabditis elegans (Nematoda).

Wegewitz V, Schulenburg H, Streit A - BMC Ecol. (2008)

Bottom Line: This is not the case in some other wild type isolates of C. elegans, among them the Hawaiian strain CB4856.We determined the kinetics of the loss of males over time for multiple population sizes and wild isolates and found significant differences.In particular, CB4856 males obtained a higher number of successful copulations than N2 males and sired correspondingly more cross-progeny.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany. viktoria.wegewitz@tuebingen.mpg.de

ABSTRACT

Background: In the androdioecious nematode Caenorhabditis elegans virtually all progeny produced by hermaphrodite self-fertilization is hermaphrodite while 50% of the progeny that results from cross-fertilization by a male is male. In the standard laboratory wild type strain N2 males disappear rapidly from populations. This is not the case in some other wild type isolates of C. elegans, among them the Hawaiian strain CB4856.

Results: We determined the kinetics of the loss of males over time for multiple population sizes and wild isolates and found significant differences. We performed systematic inter- and intra-strain crosses with N2 and CB4856 and show that the males and the hermaphrodites contribute to the difference in male maintenance between these two strains. In particular, CB4856 males obtained a higher number of successful copulations than N2 males and sired correspondingly more cross-progeny. On the other hand, N2 hermaphrodites produced a higher number of self-progeny, both when singly mated and when not mated.

Conclusion: These two differences have the potential to explain the observed variation in male persistence, since they should lead to a predominance of self-progeny (and thus hermaphrodites) in N2 and, at the same time, a high proportion of cross-progeny (and thus the presence of males as well as hermaphrodites) in CB4856.

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Persistence of males over time in different C. elegans strains and population sizes. The proportion of males after the indicated number of days is given. Every four days the populations were reduced to the number specified. Error bars are standard errors. All experiments were started with populations containing approximately 50% males. The first actual measurement was done after the first generation at day 4. A) Decrease of the male frequencies in different wild isolates at population size 75. Each point is the average of two independent measurements. B) Decrease of the male frequencies in different wild isolates at population size 150. Each point is the average of two independent measurements. C) Decrease of the male frequencies in four different population sizes in N2 and CB 4856. Each point is the average of five independent measurements. For more details on results and statistical analysis [see additional files 1, 2, 3, 4].
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Figure 1: Persistence of males over time in different C. elegans strains and population sizes. The proportion of males after the indicated number of days is given. Every four days the populations were reduced to the number specified. Error bars are standard errors. All experiments were started with populations containing approximately 50% males. The first actual measurement was done after the first generation at day 4. A) Decrease of the male frequencies in different wild isolates at population size 75. Each point is the average of two independent measurements. B) Decrease of the male frequencies in different wild isolates at population size 150. Each point is the average of two independent measurements. C) Decrease of the male frequencies in four different population sizes in N2 and CB 4856. Each point is the average of five independent measurements. For more details on results and statistical analysis [see additional files 1, 2, 3, 4].

Mentions: We first tested in how far there is variation in male maintenance among populations of different natural C. elegans isolates. Eight strains were tested at two different arbitrarily chosen population sizes (75 and 150). The proportion of males was significantly affected by the factor time, the strain studied, and also the interaction of the two. In particular, males disappeared completely from the cultures of some strains, among them N2. In contrast, in other strains, among them CB4856, the cultures appeared to reach a stable frequency of males after about two weeks (Fig. 1 and [see Additional files 1, 2]).


Experimental insight into the proximate causes of male persistence variation among two strains of the androdioecious Caenorhabditis elegans (Nematoda).

Wegewitz V, Schulenburg H, Streit A - BMC Ecol. (2008)

Persistence of males over time in different C. elegans strains and population sizes. The proportion of males after the indicated number of days is given. Every four days the populations were reduced to the number specified. Error bars are standard errors. All experiments were started with populations containing approximately 50% males. The first actual measurement was done after the first generation at day 4. A) Decrease of the male frequencies in different wild isolates at population size 75. Each point is the average of two independent measurements. B) Decrease of the male frequencies in different wild isolates at population size 150. Each point is the average of two independent measurements. C) Decrease of the male frequencies in four different population sizes in N2 and CB 4856. Each point is the average of five independent measurements. For more details on results and statistical analysis [see additional files 1, 2, 3, 4].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2483263&req=5

Figure 1: Persistence of males over time in different C. elegans strains and population sizes. The proportion of males after the indicated number of days is given. Every four days the populations were reduced to the number specified. Error bars are standard errors. All experiments were started with populations containing approximately 50% males. The first actual measurement was done after the first generation at day 4. A) Decrease of the male frequencies in different wild isolates at population size 75. Each point is the average of two independent measurements. B) Decrease of the male frequencies in different wild isolates at population size 150. Each point is the average of two independent measurements. C) Decrease of the male frequencies in four different population sizes in N2 and CB 4856. Each point is the average of five independent measurements. For more details on results and statistical analysis [see additional files 1, 2, 3, 4].
Mentions: We first tested in how far there is variation in male maintenance among populations of different natural C. elegans isolates. Eight strains were tested at two different arbitrarily chosen population sizes (75 and 150). The proportion of males was significantly affected by the factor time, the strain studied, and also the interaction of the two. In particular, males disappeared completely from the cultures of some strains, among them N2. In contrast, in other strains, among them CB4856, the cultures appeared to reach a stable frequency of males after about two weeks (Fig. 1 and [see Additional files 1, 2]).

Bottom Line: This is not the case in some other wild type isolates of C. elegans, among them the Hawaiian strain CB4856.We determined the kinetics of the loss of males over time for multiple population sizes and wild isolates and found significant differences.In particular, CB4856 males obtained a higher number of successful copulations than N2 males and sired correspondingly more cross-progeny.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany. viktoria.wegewitz@tuebingen.mpg.de

ABSTRACT

Background: In the androdioecious nematode Caenorhabditis elegans virtually all progeny produced by hermaphrodite self-fertilization is hermaphrodite while 50% of the progeny that results from cross-fertilization by a male is male. In the standard laboratory wild type strain N2 males disappear rapidly from populations. This is not the case in some other wild type isolates of C. elegans, among them the Hawaiian strain CB4856.

Results: We determined the kinetics of the loss of males over time for multiple population sizes and wild isolates and found significant differences. We performed systematic inter- and intra-strain crosses with N2 and CB4856 and show that the males and the hermaphrodites contribute to the difference in male maintenance between these two strains. In particular, CB4856 males obtained a higher number of successful copulations than N2 males and sired correspondingly more cross-progeny. On the other hand, N2 hermaphrodites produced a higher number of self-progeny, both when singly mated and when not mated.

Conclusion: These two differences have the potential to explain the observed variation in male persistence, since they should lead to a predominance of self-progeny (and thus hermaphrodites) in N2 and, at the same time, a high proportion of cross-progeny (and thus the presence of males as well as hermaphrodites) in CB4856.

Show MeSH
Related in: MedlinePlus