User:Mattakbar/sandbox

Draft 1:

Lead Section:

Gynodioecy, a breeding system that is most commonly found in certain species of flowering plants, is the occurrence of a population containing two genetically determined morphs: females and hermaphrodites. The female individuals result from a genetic mutation that impairs pollen production in the male region of plants that are usually hermaphroditic. Gynodioecy is determined by genes in the cytoplasm. Cytoplasmic male-sterilizing genes inhibit the hermaphroditic plant from producing pollen, thus, make it genetically female. Gynodioecy is seen as an intermediate stage between hermaphroditism and dioecy (the breeding system of two distinct morphs: male and female). Some notable gynodioecious species include Beta vulgaris (wild beet), Lobelia Siphilitica, Silene, and Lamiaceae. Gynodioecy is very rare, only fewer than 1% of angiosperm species are gynodioecious.

Evolution of Gynodioecy

Gynodioecy has been investigated by biologists dating as far back as to Charles Darwin. Theoretically, hermaphrodites should have the evolutionary and reproductive advantage over females in a population. Hermaphrodites can transmit their genes through both pollen and ovules, whereas females can only transmit genes via ovules. Thus, females would have to be twice as successful as hermaphrodites in order to survive in a population. It would appear that gynodioecy should not persist. However, it persists because there are certain mechanisms in gynodioecious species that favor the females over the hermaphrodites. These favorable mechanisms, known as female advantage or female compensation, include a higher seed quality and quantity as compared to hermaphrodites.

Gynodioecy is often referred to as the evolutionary intermediate state between hermaphroditism and dioecy.

Determination of Gynodioecy

Gynodioecy is determined by genes in the cytoplasm.

Rarity

Gynodioecy is a rare, but widely distributed sexual system in angiosperm species. Of all the angiosperms on Earth, only <1% of them are gynodioecious species. One likely explanation for its rarity is due to its limited evolution. Since females are at a disadvantage when compared to hermaphrodites, it will never be able to evolve as quickly. In addition, gynodioecy is rare because the mechanism that favor females in some populations operate in some plant lineages, but not others.

The reason for this variation in the rates of gynodioecy stems from certain phenotypic traits or ecological factors that promote and favor the presence of female plants in a population. For example, a herbaceous growth form is much more highly favored in gynodioecious species of Lamiaceae as compared to woody lineages. Herbaceous growth form is also associated with a reduced pollen limitation and an increased self-fertilization. A reduced pollen limitation may decrease seed quantity and quality. Woody growth form Lamiaceae are more pollen-limited, and thus, produce less seeds and seeds of lower quality, thus favoring the female herbaceous growth form.

Gynodioecy is rare, but widely distributed, because some sexual systems are more evolutionary liable to change in certain lineages as compared to others.

My topic is gynodioecy. There is not much of a well developed article on it on Wikipedia. There is a ton of research done on the subject. I plan to add a well written article on the mating system with examples and to clarify any of the ambiguous information that is currently written in the article. This is a very interesting topic and is important for understanding the separate sexes in plants.

References:

Advances in Botanical Research, Vol. 63, Chapter 4: Mitochondrial Genome Evolution and Advances in Gynodioecy

• The first chapter, 1.1 provides great insight into what gynodioecy actually is. A clear cut definition is given and the way it works is described in simple and easy to follow terms. In particular, the fact that it is seen as a transition state into dioecy, or the characteristic of having two distinct species, male and female. In addition, the descriptions of how female advantage and how that affects gynodioecy. I was unaware that gynodioecy occurs in beets. Also, the genus Silene is used as an example and a point of comparison, since it can mate in hermaphroditic, gynodioecious, or dioecious systems.

Why is gynodioecy a rare but widely distributed sexual system? Lessons from the Lamiaceae

• Illustrates how rare gynodioecy is, <1% of angiosperm families. Provides a clearly stated reason as to why gynodioecy is so rare. Also shows that gynodioecy is present in other species, unlike the Wikipedia page that only discusses it in Lobelia siphilitica.

Journal of Theoretical Biology, The joint evolution and maintenance of self-incompatibility with gynodioecy or androdioecy

• This experiment compares the differences between gynodioecious species, populations of female coexisting with hermaphrodites, and androdioecy, populations of males with hermaphrodites. One point that is made is that it is possible for gynodioecy and androdioecy to evolve from hermaphroditism, under the right conditions, which are if enough resources are allocated to the females/males and if there is a high rate of inbreeding depression. Self-Incompatibility helps to maintain androdioecy, but favors the loss of gynodioecy. Androdioecy maintains of Self-incompatibility, whereas gynodioecy has no net affect on it. Androdioecy prevents the increase of the number of Self-incompatible groups, but gynodioecy allows it.

Merging theory and mechanism in studies of gynodioecy

• Talks about gynodioecy being a type of polymoprhism. It describes how the individulas in the population become females or hermaphrodites. The cytoplasmic male sterility gene causes male sterility and turns the males into females in the population by preventing them from producing pollen. The other gene in the nucleus turns plants into hermaphrodites.

The evolution of gynodioecy on a lattice

• In this experiment, it is shown that in a gynodioecious population, the females actually have the reproductive advantage over the hermaphrodites. It takes into account how space affects gynodioecious species. Gynodioecy is less likely to evolve in plants that have more localized pollination. In addition, it is stated that a lower frequency of females should be expected in gynodioecious populations where interactions are local.

Male-biased hermaphrodites in a gynodioecious shrub, Daphne jezoensis

• It states that gynodioecy is the intermediate stage between hermaphroditism to dioecy. This experiment takes into account sex ratios, something that we discussed in class. It mentions that gynodioecy is determined by either a nuclear inheritance system or nuclear-cytoplasmic inheritance system for male sterility. Under results, it is stated that generally, females are the ones that invest more reproductive resources than hermaphrodites in gynodioecious species. However, the results of the experiment proved different.

REVIEW

This article is very well written as a first draft! You provided an abundance of information that was clear and concise. The addition of examples as well as links to pictures allows the reader to develop a better understanding of the topics being discussed.

I noticed that there are a few places where you repeat information that was already stated in your leading paragraph and I don't think this is absolutely necessary. Additionally, under the sub-heading titled "Rarity," I would suggest explaining the term "herbaceous growth form" since it is significant term in the paragraph and others may not know what it means or how it really connects to your topic. You can always link any definition or term to its own Wikipedia page if you find yourself over explaining and possibly diverging from your own topic.

Lastly, there are other minor details such as grammatical errors, adding in-text citations, and making sure to italicize genus and species names of different organisms. Overall, the content was informative and the article was written in a neutral tone.

-Darling Rojas

RESPONSE TO PEER REVIEW

Thank you for your peer review. I will try and cut down the repetitiveness as much as possible in my next draft. I will also try and clarify the term herbaceous growth form; I agree, many people may not know exactly what that means. Also, I was look for those grammatical errors and correct them in the next draft. Thanks.

-Matt Akbar