Chromatid Abnormalities in Meiosis: A Brief Review and a Case Study in the Genus Agave (Asparagales, Asparagaceae)

Abstract

The genus Agave is distributed in the tropical and subtropical areas of the world and represents a large group of succulent plants, with about 200 taxa from 136 species, and its center of origin is probably limited to Mexico. It is divided into two subgenera: Litaea and Agave based on the architecture of the inlorescence; the subgenus Litaea has a spicate or racemose inlorescence, while plants of the subgenus Agave have a paniculate inlorescence with lowers in umbellate clusters on lateral branches. As the main conclusion of this study, a hypothesis rises from the described observations: frying pan-shaped chromosomes are formed by sister chromatid exchanges and a premature kinetochore movement in prophase II, which are meiotic aberrations that exist in these phylogenetic distant species, Agave stricta and A. angustifolia since ancient times in their evolution, and this may be due to genes that are prone to act under diverse kinds of environmental stress.