achiasmate

achiasmate

[‚ā·kī′az‚māt]
(cell and molecular biology)
Pertaining to meiosis that lacks chiasma.
References in periodicals archive ?
1975) Achiasmate meiosis in the Fritillaria Japonica group I.
All his life, Michael White was fascinated by anomalous and hard-to-explain meiotic systems, such as the bizarre mechanisms of gall midges, or the achiasmate male meiosis of some mantids and eumastacids (White 1965a,b; 1970).
Like sex chromosomes, most supernumerary chromosomes are achiasmate and so are subject to a similar progressive accumulation of deletions and heterochromatic, repeated DNA (Green, 1990).
It is worth noting that spermatogenesis of Tetrigidae (Tettigidae in old terminology) was already well known through studies of Mary Theresa Harman (1877-1961) and William Rees Brebner Robertson (1881-1941) (Harman 1915, 1920; Robertson 1916 a,b), and although males are not achiasmate, tetrigids are characterized by extreme distal chiasma localization in autosomal bivalents, which is almost analogous to an achiasmatic situation (see below).
Not only could one sex be totally achiasmate as in Drosophila, in many praying mantids and eumastacid grasshoppers (where no case of both sexes being achiasmate has ever been reported), but in many species chiasmata were strongly localized in more or less constant positions along bivalents.
In this sense, he was always fascinated by 'anomalous' types of meiosis, especially those in which one of the sexes is achiasmate.
Mantids and their male meiotic process were of profound interest to White because of their wide variation in diploid numbers, their varied and complex sex-determining mechanisms, and because the existence of male achiasmate meiosis posed problems to the mechanism that maintained the integrity of bivalents to allow normal segregation (White 1977, Wolf 1994).
Undoubtedly White found satisfaction greater than that of science alone when (contra Oarlington) he described an achiasmate meiosis in a mantid during his first period of research in the United States in the late 1930s.