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Abstract Detail

Molecular Ecology and Evolution

Cruzan, Mitchell B. [1], Jered, Thompson [2].

Autogamy depression and the production of high-fitness selfed offspring in Mimulus guttatus.

Mutation accumulation in plants differs from animals, which have separate germlines that are set aside early in development. The potential for accumulation of genetic mutations and epigenetic modifications is much greater in plants because of extensive somatic growth intervening between zygotes and the formation of gametes. The large number of mitotic divisions occurring during vegetative growth may generate a large mutational load that is predicted to depress the fitness of inbred offspring. Inbreeding depression can be particularly severe after autogamous pollinations because of mutations that accumulated during the growth of each stem. Somatic mutational load may be alleviated to some extent by cell lineage selection due to competition among cell lineages in the apical meristem. The exposure of mutations to selection during pollen growth also has the potential to filter deleterious mutations. We investigated the potential for somatic mutation accumulation, cell lineage selection, and gametophytic selection in Mimulus guttatus by conducting limited and excess self-pollinations within the same flower (autogamy) or between two different stems on the same plant (geitonogamy). Levels of ovule abortion were greater after autogamous compared to geitonogamous pollinations. Unexpectedly, plants grown from autogamous crosses had higher survival, greater biomass, and higher frequencies of flowering than plants produced by geitonogamous self-pollinations. No effects of limited vs. excess pollen were found for any of the seed set or plant growth measurements. While a number of previous studies have found effects of autogamy depression on levels of seed and fruit abortion, to our knowledge, this is the first study to examine the effects of autogamy vs. geitonogamy on offspring fitness. These results suggest we have much to learn about the potential for cell lineage selection and gametophytic selection to affect plant fitness and adaptive evolution.

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Related Links:

1 - Portland State University, Department Of Biology, PO Box 751, Portland, OR, 97207, USA
2 - Portland State University, Biology, Portland, OR, 97207, United States

Autogamy depression
Cell lineage selection
gametophytic selection
somatic mutation.

Presentation Type: Oral Paper:Papers for Topics
Session: 61
Location: Salon 15/16/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 11:00 AM
Number: 61012
Abstract ID:282
Candidate for Awards:None

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