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Mimulus lewisii (low to mid-elevation)
Bee pollinated
Pink petals
Landing Platform
Small Amounts of nectar
Mimulus cardinalis (mid to high elevation)
(Bird Pollinated)
Reflexed petals, no landing platform
Large amounts of nectar
Red Petals
F2 generation plants were placed in a grid in the field and scored for pollinators.
•Yellow pigment reduces visits by bees.
•High nectar volume increases
visits by birds.
How might shifts in pollinators affect speciation rates?
Two different pollinators acting on one species could result in reproductive isolation and speciation
Figure 1 Near-isogenic lines of M. lewisii and M. cardinalis with alternate alleles at the YUP locus. a, b, M. lewisii; c, d, M. cardinalis.The wild-type allele at the YUP locus (a, c) has been substituted by introgression with the allele from the other species (b, d). Flowers in each NIL pair (a and b, c and d) are full siblings.
YUP yup
yup YUPBradshaw and Schemske. 2003. Nature 426:176-178
YUP yup
yup YUP
The YUP gene controls carotenoid (yellow pigmentation).
When it is active/dominant it suppresses yellow pigment production.
When it is recessive it allows yellow pigment production.
Raphanobrassica, an allotetraploid, was first created by the Russian, G. Karpenchenko in 1928. He crossed two species in the Brassicaceae, Radish, Raphanus sativus (2N = 18) X Cabbage, Brassica oleracea (2N = 18)
Raphanobrassica has 2N = 36-- so it has a complete diploid set of chromosomes from each parent. Karpenchenko had hoped to get the tops of the cabbage and the bottoms of a radish. Unfortunately the result was the tops of the radish (shown above) and the bottoms of the cabbage. It is cultivated in Scotland for fodder for sheep and cattle.