Non-Mendelian Genetics

Ever wonder why some traits don't follow simple dominant-recessive patterns? In incomplete dominance, neither trait dominates, causing them to blend together. For example, when a white snapdragon (ww) crosses with a red snapdragon (RR), you get pink flowers (Rw) - a perfect blend of both parents.

Codominance is different - both traits show up equally rather than blending. When a white chicken (ww) mates with a black chicken (BB), their offspring have speckled feathers (BW) showing both colors distinctly.

Many characteristics like height, skin color, and weight result from polygenic inheritance - multiple genes working together to create a range of possibilities. This explains why these traits have so much variation in human populations.

Try This! Look at your own traits like eye color, hair texture, or height. Can you identify which might follow non-Mendelian patterns of inheritance?

Finally, sex-linked inheritance refers to traits carried on the X chromosome. Conditions like colorblindness and hemophilia appear more frequently in males because they only have one X chromosome, while females have two and typically need two affected X chromosomes to show these conditions.