1. Ss  ss -> Ss and ss in a 1:1 ratio S s s s Ss ss Ss yields a short-styled flower. Heterostyly is controlled by a gene S with simple inheritance: ss yields a long-styled flower.

2. Ss  ss -> Ss and ss in a 1:1 ratio S s s s Ss ss Ss (short-styled) flower  Heterostyly is controlled by a gene S with simple inheritance: ss (long-styled) flower. thrum x thrum gives 3:1 thrum:pin, ie. Ss X Sx = SS, Sx, Sx, ss pin X pin gives all pin i.e. ss X ss = ss

3. Two kinds of self-incompatibility: Gametophytic: S 1 S 2 female  S 1 S 3 male yields inhibition of S 1 pollen, not of S 3 pollen --- happens on the stigma Sporophytic: No S 1 S 2  S 1 S 3 yields inhibition of pollen Only the same two alleles yield inhibition --- happens in the style

4. Introduce papillae and pollen size

6. G - style length S p - stigma papilla length I - self incompatibility P - pollen grain size A - anther height The Primula supergene - short-style flowers have large pollen grains and and small stigmatic papillae - long-style flowers have small pollen grains and large stigmatic papillae So big pollen grains land on long styles where there are big stigmatic papillae. Little pollen grains land on short styles where there are small stigmatic papillae The self incompatibility is sporophytic.

7. aob.oupjournals.org/cgi/reprint/78/6/759.pdf

8. Self-incompatibility: Antibody-antigen response: protein found in styles of petunias with incompatible pollen tubes, not with compatible tubes - mutations indicate two subgenes with different actions, one the pollen reaction and one the style reaction - tetraploids between incompat diploids fail (as long as different alleles are present the antigen-antibody response proceeds. multiple alleles are found in species to allow a diverse definition of self (45 alleles in 500 oenothera organensis plants, at least 75 in T, repens and 150 in T. pratense ) --- Grant 1975