Recent comments in /f/askscience

Dubanx t1_j9tst9o wrote

Reply to comment by Zchwns in Why is urine yellow? by nateblackmt

No problem. It's not just limited to asparagus pee too. Taste & Smell are exceptional in how much they vary from one person to another. A famous example is "phenylthiocarbamide". One person spilt some in a lab setting and was confused as to why everyone around him was talking about the smell.

Another example is how certain vegetables, such as spinach, taste terribly bitter to some people and perfectly fine to others. A common trope is a mother screaming at her son/daughter to eat their veggies while the dad sits quietly because he also hates spinach.

Mom lacks the genes which make them taste bad while the children and dad do. The kids aren't just being picky, they literally taste significantly differently between mother and child.

14

GypsyV3nom t1_j9tsldx wrote

Reply to comment by Zchwns in Why is urine yellow? by nateblackmt

Taste and smell have some pretty insane under-the-hood processing that occurs in the brain. There are only about 400 different receptors in the human nose, but the different responses of those 400 receptors to odorants allows humans to detect over one trillion distinct scents. And that's just for humans, who have a relatively poor sense of smell compared to other mammals

10

Dubanx t1_j9tqj7x wrote

Reply to comment by Zchwns in Why is urine yellow? by nateblackmt

People's sense of smell & taste tend are known to be heavily dependent on genetic factors, but are super complicated. It's my understanding that these aren't determined by a single gene but the interactions between multiple genes. So they're poorly understood as a result. In general, smell and taste aren't something that gets determined by a single recessive or dominant gene.

For what determines excretion, I just don't know.

12

Zchwns t1_j9tou8g wrote

Reply to comment by Dubanx in Why is urine yellow? by nateblackmt

Do we know whether these genetic traits are dominant or recessive? I’m curious if it’s rarer to have both genetic traits expressed vs no expression of either.

8