Date: Wed, 10 Sep 1997 23:02:21 -0600 From: cfrazie@unm.edu (Chris Frazier) To: cp@opus.hpl.hp.com Message-Id: <aabcdefg3490$foo@default> Subject: Re: Nepenthes x williamsii (and hybridizations)
>Now if you took a male N x hookeriana and crossed it with a female N x
>hookeriana, (created the F2 hybrid) the offspring will have a somewhat random
>mixture of chromosomes from what was originally N. rafflesiana and N.
>ampullaria. In theory, if you raised enough F2 seedlings you should come up
>with plants that are indistuinguishable between N. rafflesiana and N.
>ampullaria and everything inbetween. Most, however, will be somewhere
>inbetween.
Actually, it would be really interesting to know what people have gotten
when they cross-pollinate hybrids and grow up the progeny from seed.
Nepenthes have 40 chromosomes. Crossing two hybrids *should* yield plants
in which nearly every one looks different from its siblings (there are
40x39x38x...1 different combinations of chromosomes). But that supposes
that the character of pitcher plants is derived from a lot of genes and
that these genes are spread out throughout the 40 chromosomes. At the
other extreme, maybe only a few genes are responsible for the differences
between species and maybe they are highly 'linked' that is to say close
together on the same chromosome. If that were the case, then a cross
between two hybrids would yield only three classes of offspring; half would
look just like the hybrid parents and a quarter would look exactly like the
original parent species.
While this latter scenario is pretty unlikely, there are a lot of other
techical reasons why the offspring from a cross between two hybrids might
not be as diverse as you would expect from the first scenario.
Observations on what people have really gotten would help a lot in
understanding the evolution of Nepenthes, particularly the role of natural
hybridization : - )
Chris
-----------------------------------------------------------
Chris Frazier
Dept. of Biology, UNM
Albuquerque, NM, USA 87131
(505) 277-0683
Homepage: http://redtail.unm.edu/
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