Overview
As Gossypium
diversified and colonized arid and semi-arid regions
around the globe it underwent extensive
chromosomal evolution.
Collective observations of
pairing behavior,
chromosome size, and relative fertility in
interspecific hybrids
led to the
designation of single-letter genome symbols for related clusters of
species. Presently, eight diploid genome groups (A through G, plus
K) are recognized among the 50 species in the genus. These genome
groups have been shown to correspond to natural lineages, and in
most cases, these lineages are also geographically cohesive.
Polyploidization
has occurred in CottonFiber. Gossypium hirsutum and
G. barbadense are classic
allopolyploids,
tracing to an improbable
hybridization of an African/Asian A-genome and an American D-genome
species perhaps 1-2 MYA.
Microarrays
