Copy number analyses of DNA repair genes reveal the role of poly(ADP-ribose) polymerase (PARP) in tree longevity.

Long-lived organisms are exposed to the risk of accumulating mutations due to DNA damage. Previous studies in animals have revealed the positive relationship between the copy number of DNA repair genes and longevity. However, the role of DNA repair in the lifespan of plants remains poorly understood.

Low mutation rates promote the evolution of advantageous traits by preventing interference from deleterious mutations.

We studied how mutation rates promote the evolution of advantageous traits in an asexual population. First, to examine the effects of mutation rates on the evolution of an advantageous trait (high competitive ability), we carried out simulation analyses with competition between individuals for survival. Second, to examine the mechanism underlying the promotion of advantageous trait evolution, we calculated the probabilities that new favorable effects of mutations on the phenotype were acquired and that existing favorable effects were maintained.

Ovule and seed production patterns in relation to flower size variations in actinomorphic and zygomorphic flower species.

Zygomorphic flower species tend to show lower flower size variation than actinomorphic flower species. Have these differences also brought an association in ovule and seed production that has arisen due to natural selection in these species? Flowers were collected from 29 actinomorphic and 20 zygomorphic flower species, and fruits were collected from 21 actinomorphic and 14 zygomorphic flower species in Miyagi and Aomori prefectures, in Japan. The coefficient of variations (CVs) of flower sizes, mean ovule sizes of flowers, ovule numbers of flowers and mean seed sizes of fruits were calculated.

Evolution towards minimum ovule size? Ovule size variations and the relative sizes of ovules to seeds.

Background And Aims: Is there selection minimizing the costs of ovule production? Such selection should lead to a smaller ovule size in relation to seed size and, at the same time, smaller variation in ovule size within plants, the latter because the minimum structures and resources for functioning of ovules should be the same among ovules. Additionally, within species, ovule size should not depend on the plant's resource status.

Methods: To confirm these predictions, we examined ovule and seed production for a variety of species.