Some Modified Phenotypic Ratios Produced by Gene Interaction
| Type of gene interaction | 9 A_B_ | 3 A_bb | 3 aaB_ | 1 aabb | Phenotypic ratio | Example |
| None - simple dominance | 9 | 3 | 3 | 1 | 9:3:3:1 |
Pea seeds |
| Complementary gene action | 9 | 7 | 9:7 |
Cyanide in Clover |
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| Recessive suppression by aa acting on bb | 9 | 3 | 4 | 9:3:4 | ??? | |
| Recessive epistasis of aa acting on B and b alleles | 9 | 3 | 4 | 9:3:4 | Coat Color Black:Brown:Albino |
|
| Dominant epistasis of A acting on B and b alleles | 12 | 3 | 1 | 12:3:1 | Summer Squash white:yellow:green |
|
| Dominant epistasis of A acting on B and b alleles | 12 | 3 | 1 | 13:3 | Chickens white:colored |
|
| Duplicate genes (tetraploidy) | 15 | 1 | 15:1 | Shepherd's Purse Round : Narrow |
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How would you explain 9:6:1? Can you give an example?
Text iGenetics by Peter J. Russell
This web site is provided for instruction in Botany and Zoology 342
by Kenneth G. Wilson,
Professor of Botany
Miami University
wilsonkg@muohio.edu