Question

PLEASE HELP... Why are observed ratios often different to expected ratios in genetics?

Answer 1

because of the random. Sometimes you won't find the results just like your maths, because of the random. Let me make more clear. If you math found that a dog has 50% of chance to be a green eye dog, if is born 10 dogs, is not necessarily 5 dogs with green eyes and five with black eyes, all the dogs could have black eyes, or green eyes, or 6/4. Did you understand? the random of the life could make the results different of your maths

Answer 2

^Yes that's correct. You would also find that the more dogs are born, the better the observed results align with the expected results. To expand further - in a sense, what the 50% chance green vs black eyes means is that for each dog-to-be-born, you're flipping a coin. The results of one coin flip do not impact the results of another whatsoever. Anyone who has flipped a coin knows sometimes, you can get seemingly odd results! But, after flipping the coin 100,000 times, you'll find that the observed ratio becomes closer and closer to what you expect (0.50).

I think genetic mutations or errors during meiosis could play a tiny role too, as well as recombination perhaps if you didn't already factor that in.

P.S. - Fun fact...technically I lied up there. Apparently the ratio is 0.51...I don't understand it, but if you want to take a look: http://www-stat.stanford.edu/~susan/papers/headswithJ.pdf :D

Answer 3

Thank you! :D

Answer 4

^^