If a child is 50% DNA from either parent, why can it look like it has all features from only one side?
In: Biology
Looks reflect a tiny fraction of the DNA. The vast majority of the information in DNA has to do with internal processes. Outward appearance just isn’t that important, from an evolutionary survival perspective.
Let’s say you have 50 random coin flips. Only three of those affect appearance. If those three come up tails, the kid looks mostly like the tails-side parent. Now, the numbers are way larger and more complex than that but it gets the idea across. Only a few of the total coin flips involve appearance.
You are getting into dominant and recessive genes. Depending on which genes get passed on and which ones are dominant and which ones are recessive; that will determine what the child looks like. This can get pretty hairy quickly.
Bcz not all genes express… There are two alleles of a gene in every human. The two alleles come from two parents. Sometimes one of them is dominant and the other one is recessive. So, the dominant one would determine that particular character (phenotype)
You say “all features”, but you don’t usually recognize people by more than a few particularly distinctive features. That’s why you can often recognize people by seeing only the top or bottom half of their face.
If a child has the same distinctive mouth and face shape or whatever features you associate with one parent, and his other features are less distinctive, you might see that child as looking completely like that one parent.
Disregarding the genetics side of things, its not even plausible from a statistical point of view. Imagine having a deck of blue cards and a deck of red cards. Mix them together and then divide to two equal sized decks. What is the probability you end up with the original red and blue deck?
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Because people that make that observation tend to focus on just the face.
Sure, someone might have their mother’s eyes, nose, and hair but they also have their father’s fingers toes, baldness, etc that no one pays attention to or only happen at adulthood
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