parthanogenesis

Julian Blanc Juarez mcbjjbj at leonis.nus.sg
Fri Oct 8 05:15:25 EST 1993


[...]
: Well, my own opinion as to why this has/would not occur is more for
: physiological than "evolutionary" reasons:  males don't do parthenogenesis
: because if they did, they'd be called females.  My understanding is that
: "male" and "female" are defined in general by the relative motility of
: their gametes (i.e. "sperm/pollen" are motile, "eggs/ova" are not), and
: consequently, in those species which "give birth", by who bears the young
: or lays the egg.

Not necessarily. In the Hippocampi (sea horses), males give birth to the
offspring. 

: >My last question is simply: in 
: >what types of organisms does parthanogenesis occur?  I know it occurs in 
: >insects, what about other arthropods, plants (I believe it does), other 
: >animals, fungi?  Thanks for any replies.

Although it doesn't occur naturally in higher vertebrates, it has been
possible to artificially induce it in turkeys as well as in mice, but
in the latter the parthenogenetic offspring dies before it's born
(presumably due to genomic imprinting - ie certain genes must be received
from the father for proper development to occur)

: As far as plants go, I think the runners that plants such as strawberries
: and (I think?) grasses put forth by way of asexual reproduction are
: considered a form of parthenogenesis.  There is also a species of lizard
: that parthenogeneses (would that be the verb form?).  Probably there are
: more but I don't know of any.

I guess the verb form would be to parthenogenerate. The thing with
strawberries et al is that the clones are generated from vegetative (ie
diploid) tissue, whereas in most true parthenogenonts the offspring is
haploid (having arisen from the gametes). If I remember well, however,
there are at least two different parthenogenetic strategies, one of which
bypasses meiosis altogether, thus giving rise to diploid offspring. 


Julian Blanc



More information about the Mol-evol mailing list