Monday, July 1


Meiosis is a term used to describe division of cells prior to sexual reproduction. It's used by bacteria, by plants, by animals, and of course by mammals.

Meiosis follows a long preparatory process, and is similar in some ways to the cell division process used when growing. Generally speaking, you start with a single diploid cell (which has chromosome pairs) and wind up with four haploid cells (which has unpaired chromosomes waiting to pair up with those from another organism).

In mammals (including humans), female meiosis happens before the mammal is born (for humans, it's when the female is about five months old) while male meiosis does not begin until after puberty (and presumably continues for most of the rest of the life of the male).  Also, in female mammal meiosis, only one of the set of four haploid cells produced by meiosis gets retained as an Oocyte (an "egg").

Note also that sexual reproduction includes asexual element: mitochondria. Mitochondria are haploid cells which are essential to metabolism (essential to life). Mitochondria are retained during meiosis in both sexes, but after sex only the mother's mitochondria are retained. Retaining the integrity of mitochondria might have something to do with why female meiosis happens before birth.  Mitochondria are characteristic of "animals". "Plants" have something else to keep them alive (chlorophyll).

Genetic searching is a robust searching technique used by computer programmers when dealing with a search problem which is too intricate for a lesser search algorithm. The details of this kind of algorithm are patterned after sexual reproduction and the behavior of algorithm is in some sense similar to the concept of "evolution".  In other words, this kind of system can be useful when dealing with complicated situations.

There's also something interesting in how much meiosis matters even when it's "not happening". This time is called "interphase" in literature describing meiosis. Normal people would probably call this "preparation".

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