Talk:Apomixis

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A summary of this article appears in Asexual reproduction.

I think apomixis is used with all organisms, not just plants. Parthenogenesis also. Actually parthenogenesis and apogamy are types of apomixis!

While apomixis may also be used for other organisms, it is primarily used in reference to plants. While I cannot speak in regards to usage in other organisms, I do know a bit about its usage in botany.

Unfortunately, the wide-range of overlapping and redundant terminology, along with differences in usage between disciplines, has caused considerable confusion in many terms relating to asexual reproduction. However, in apomixis literature, parthenogenesis, defined as the development of an embryo in the absence of fertilization, is considered one of the required components of apomixis, and not a type thereof. By definition, apomixis, which in plants is defined as reproduction through seed in the absence of fertilization, requires parthenogenesis in all its forms. However, the apomictic process in plants is considered to require two other components, namely 1) absent or abnormal meiosis and 2) initiation of endosperm development, either through fertilization (called pseudogamy due to the fertilization only of the polar nuclei) or spontaneously.

In plants, such a distinction between apomixis and parthenogenesis is important, as some species are also capable of producing haploid offspring through seed - which occurs in the presence of meiosis alongside parthenogenesis. This is often also considered a form of apomixis. Unfortunately, such a consideration does not reconcile with the requirement that apomixis have absent or abnormal meiosis. This contradiction unfortunatley represents actual contradiction in the literature, largely divided between genetics/ecology subdisciplines. Regardless, parthenogenesis is required in apomixis, but is not a type thereof.

Depending on which source you choose to use, apogamy could refer either to asexual reproduction as a whole, to apomixis in particular, or to a subtype of apomixis (sporophytic apomixis/adventitious embryony). In reality, however, this term is not used in plant apomixis literature.

When I have more time, I will clean up this article, as much of the information currently does not reflect the terminology used for apomixis in plants, despite the current plant focus. Ultiam 04:00, 24 April 2007 (UTC)