Polygenic Inheritance

[GDT]

Hello folks,

 

I'm having a tough time understanding the difference between incomplete dominance and polygenic inheritance. When I search on the internet, I keep getting answers like incomplete dominance is a blending of traits, like with a red rose and a white rose becoming a pink rose. Whereas polygenic inheritance is more blending genes like skin color.

 

Now...to me these seem like the same things. You're blending genes together. From multiple things comes one thing that shares a blend of characteristics. What am I missing here?

 

Thanks!

GDT

[Mr Skeptic]

The difference is in the number of genes. If you have one gene for color with two different alleles, you can get 2 or 3 different phenotypes (dominant, recessive, and co-dominant). For example the genotypes might be RR, Rr, rr. Whereas if there are multiple genes involved, presumably each with more than one allele, you can get lots and lots of variety. In this case the genotypes might be AABbCCDd, aaBBCCDd, AaBbccDd.

[GDT]

Fair enough! Thank you for the explanation.