asexuality in pathogens

Kathie Hodge kh11 at cornell.edu
Tue Dec 8 17:21:16 EST 1992


In article <1992Dec5.002034.1 at nickel.laurentian.ca> ,
s1400070 at nickel.laurentian.ca writes:
>Since most parasitic invaders reproduce assexually and may have many
generations
(stuff deleted)

Why do pathogens tend to reproduce asexually?

I work on a group of obligately insect-pathogenic fungi, the
Entomophthoraceae.  The dozen or so genera in the family appear to be
strictly asexual, and are descended from ancestors with both sexual and
asexual forms of reproduction.  Have they given up sex because there is
selection against it?  Or perhaps they've just lost it through lack of
use: given that most insect infections are started by a single spore,
there might not be much opportunity for recombination.

Wouldn't pathogens benefit by the production of rare offspring in the
same way that their hosts do?  Note also that these fungi are haploid,
and that parasexuality is also unknown.

Kathie Hodge
kh11 at cornell.edu



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