Abstract Detail

Population Genetics/Genomics

Schwoch, Jaime [1], Cruzan, Mitchell [2].

Accumulation of Somatic Mutations during Vegetative Growth.

In plants, vegetative growth occurs prior to the formation of gametes, which allows somatic mutations to be passed on to the next generation. We expect that the accumulation of somatic mutations may be nonrandom due to competition among lineages of stem cells during vegetative growth that favors beneficial mutations and eliminates deleterious mutations. Deleterious mutations may be culled further by pollen competition and selective embryo abortion. In two separate experiments, we tested for the effects of somatic mutations by growing clonal replicates of Mimulus guttatus under novel conditions and testing for the homozygous effects of somatic mutations unique to individual stems by contrasting the growth of progeny from self-pollinations within (autogamy) and between (geitonogamy) stems of the same plant. We expected progeny from autogamous crosses would be homozygous for a proportion of somatic mutations while progeny from geitonogamous crosses would be heterozygous for acquired mutations. Consistent with this expectation, the variance among offspring growth among stems was greater for autogamous than geitonogamous progeny from the same stems (P < 0.001) and this result was similar in both experiments. Selective values (s) of mutations unique to each stem varied from deleterious effects of homozygosity to a prevalence of beneficial effects expressed as higher rates of survival and growth of autogamous progeny. There was a positive association between selective effects and the variance among geitonogamous progeny (P < 0.02) indicating that deleterious mutations were recessive while beneficial mutations were more likely to be expressed when heterozygous – a result that is consistent with cell lineage selection. We are identifying sequence variants unique to clonal replicates using RNAseq. Our results suggest that mutation accumulation during vegetative growth is non-random due to the effects of selection acting on sequence variants prior to seed dispersal.

1 -
2 - Portland State University, Department Of Biology, 1719 SW 10th Ave, SRTC Rm 246 - Biology, Portland, OR, 97201, United States

Keywords:
Mutation
Inbreeding
Autogamy
Geitonogamy
Selection.

Presentation Type: Oral Paper
Session: 47, Population Genetics and Genomics II
Location: 101/Mayo Civic Center
Date: Wednesday, July 25th, 2018
Time: 3:00 PM
Number: 47007
Abstract ID:866
Candidate for Awards:Margaret Menzel Award