It has been hypothesised, that our observations of the comparison between lower plants and higher plants, for example, might suggest that evolution of diploidy may have been the necessary pre-requisite for the evolution of multicellularity. Is there any solid molecular understanding of as to why that may be. Please cite some of the useful sources, if possible. Thank you.
One back question:
Who hypothesised this?
And just two notes:
1. Sex is a complicated phenomenon variously defined in different organisms. So I cannot clearly understand what do you exactly mean writing 'evolution of sex'?
2. There are many bisexual unicellular organisms existing for a long time without significant evolutional transformations... and if you compare algae and so on with higher plants, you should keep in mind that the first group is polyphyletic and its evolution occur in many different directions and not always due to multicellularity. Such a way I don't see any ways to prove this at least in general view.
What organisms do you study?
may be diversity and linkage of gene helps in the natural selection so one can survive
One back question:
Who hypothesised this?
And just two notes:
1. Sex is a complicated phenomenon variously defined in different organisms. So I cannot clearly understand what do you exactly mean writing 'evolution of sex'?
2. There are many bisexual unicellular organisms existing for a long time without significant evolutional transformations... and if you compare algae and so on with higher plants, you should keep in mind that the first group is polyphyletic and its evolution occur in many different directions and not always due to multicellularity. Such a way I don't see any ways to prove this at least in general view.
What organisms do you study?
It has been suggested that it evolved not to create diversity, but to control it. By having two organisms merge their genomes, you homogenize the population. This may help control deleterious mutation is more complex multi-cellular organisms.
Hi Maria,
I meant to say " evolution of diploidy" instead of "evolution of sex", but alas, as I was writing an essay on the evolution of sex I absent-mindedly asked the wrong question. Nonetheless, it has been corrected now.
With regards to the reference, here it is: Calow, P. (1978) Life Cycles: An Evolutionary Approach to the Physiology of Reproduction, Development, and Ageing. United Kingdom: distributed in the U.S.A. by Halsted Press.
Having said all of this, while evolution of sex is a complex phenomenon, in terms of the components, which form the mechanistic of the sexual machinery, it can be treated as a singular event in the evolutionary process. While my question was meant to be about the evolution of diploidy, it could be argued that evolution of sex (not the prokaryotic version) has also played a major role in the evolution of multicellularity. The book I have referenced gives you a sort of evolutionary ecology explanation, for roles of both Evolution of diploidy and sex in evolution of multicellularity. you can also refer to the works of Maynard Smith, which would give you a more extensive framework on what I mean, Which brings me to your question as to "what I mean by evolution of sex". Well the following book by Graham is about the evolution of sex, and as I mentioned before, while it treats this phenomenon (like any other evolutionary phenomenon) as a multi factorial evolutionary event, the term "evolution of sex" is still considered.
Graham, B. (1982) The Masterpiece of Nature: Evolution and Genetics of Sexuality. Netherlands: Kluwer Academic Publishers.
With regards to the algae; I did not mention anything about algae at all!
With the correction I made it should make more sense now.
I basically want to know if there is any molecular evidence/understanding as to whether there is a link between the diploidy and multicellularity.
Thank you Rogini, I have indeed watched this great lecture. Alas, it does not touch on any molecular evidence of potential relationship between "diploidy" and multicellularity, which I incorrectly mixed up with sex.
To have any "molecular evidence" you will need to have some expectation of the molecular pattern to study. What kind of pattern do you expect? What kind of organism do you need to compare/analyse? Will you compare multicellular organisms derived from ancient diploids and with those derived from ancient haploids?
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