Take the 2-minute tour ×
Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It's 100% free, no registration required.

Background

General concept

According to Cochran and Harpending (2013), mothers transmits on average a number $x$ of new mutations to their offspring. This number $x$ is independent of the age of the Mother. Fathers, however transmit a number of new mutations to their offsprings that is very much dependent on the age of the father for developmental reasons. In short (and probably poorly stated due to my lack of knowledge in physiology), spermatogenesis is a continuous process that occurs during the lifetime of the individual while the creation of ovules occurs once and are then stocked.

Human example

According to Kong et al.(2012), in humans the mother transmit on average $15$ new mutations and the father transmit on average $25 + 2(g-20)\space\space$ new mutations, where $g$ is the age of the father. For example, a 30-year-old father transmits $25 + 2(30-20) = 45\space\space$ new mutations. (This approximation holds only for men older than 20 years).

Question: What about plants?

  • Do you think that in plants too male and female organs (or individuals for (gyno/andro)diocious species and eventually sequential hermophroditic species) transmit a different number of new mutations for similar developmental reasons?

  • Do you think that in plants the number of new mutations is age-dependent in males but not in females alike in humans?

  • Do we have any estimate of the sex and age-specific number of new mutations transmitted in plants?

share|improve this question
    
The age dependency for males is because of continuous spermatogenesis (older spermatogonia might acquire more mutations). Oogenesis however, happens quite early in development and oocytes are locked at metaphase. Female age also matters and is evident in case of aneuploidies. I dont know the mutation rates in plant germline but I suppose it is higher in pollens because they are more exposed to sunlight and other environmental factors. –  WYSIWYG Jul 24 at 4:50
    
Why would age matter in females in case of aneuploidy? It is not evident to me. I didn't think of external factor such as sunlight, that's interesting. So, does pollen go through continuous spermatogenesis in plants too but not ovules just like in animals so that we could expect the same pattern than in animals even increased by the sunlight. @WYSIWYG Thank you –  Remi.b Jul 24 at 7:28
    
female age correlates with non-disjunction of chromatids- leading to aneuploidy. See this.. Usually in many plants flowering happens throughout life (both gametes produced). Some plants however flower only once per lifetime. For some it is periodic. So depending on the flowering pattern, the spontaneous mutation rates may vary. –  WYSIWYG Jul 24 at 8:00
    

1 Answer 1

up vote 2 down vote accepted

From Whittle and Johnston (2006):

Specifically, human epidemiological data and/or nucleotide substitution rates of selectively neutral DNA (which equals the mutation rate, Kimura, 1983; Miyata et al., 1987) have shown that more mutations occur in the male than in the female germ line for numerous animal taxa (e.g. humans, mice, chickens, and sheep) and in older rather than younger human males, patterns that each agree with the cell-division hypothesis (i.e. more DNA replications in males and in particular older males; Penrose, 1955; Risch et al., 1987; Becker et al., 1996; Moloney et al., 1996; Li, 1997; Green et al., 1999; Crow, 2000; Li et al., 2002; Makova and Li, 2002). Other data, however, have indicated that the mutation bias reported relative to gender and male age are not generally well correlated with the number of germ cell divisions and that other factors could explain these trends, such as methylation patterns, differential repair, metabolic rates, and preferential transmission of mutations to pro- geny from older males (Risch et al., 1987; Martin and Palumbi, 1993; Drost and Lee, 1995; Bromham et al., 1996; Hurst and Ellegren, 1998; Martin, 1999; Crow, 2000; Huttley et al., 2000; McVean, 2000; Sommer et al., 2001;Hebert et al., 2002; Hurst and Ellegren, 2002; Kumar and Subramanian, 2002; Li et al., 2002; Bartosch-Harlid et al., 2003).

…so basically we don't quite know whether difference in gametogenesis between males and females lead to more sex and age-specific mutation rate!

However, Whittle and Johnston (2006) in reviewing many articles also show that old seeds are more likely to carry chromosomal aberration and that old individuals are more likely because of the instability of their metabolism to transmit more mutations but that would be sex independent and would not result in different gametogenesis as I was expecting in asking this question. Also the kind of mutations that become more frequent with all parents are chromosomal abnormalities or important deletion but not so much substitutions (which was also what I was interested in when asking).

Thanks @DevashishDas for finding this article. This other one was interesting as well.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.