So the gene for e.g. blue eye colour codes for the amino acid sequence that forms a blue pigment. The gene for sickle cell anaemia has a mutation that changes the shape of haemoglobin.
How are attibrutes such as the shape of facial features, predisposition to balding or mental health issues etc. genetically inherited? Do they all really happen because of different proteins?
To expand on what u/sethjoness said, protiens are analagous to the concrete used in construction, but they’re also a signaling tool. For instance, if you have a gene that codes for a protein that accelerates bone growth and you have that gene turned on for longer than someone else, your bones are going to be bigger than theirs. Different growth speeds mean different shapes and sizes of your body parts, while different timings mean subtly different arrangements.
A lot of these things are one or two steps removed. For instance, a hormone issue that adjusts your metabolism might indirectly affect your muscle mass, which changes your body shape. Or a reduced production of signaling proteins causes a drop in neuron repair causing cognitive degeneration.
Bonus fact: there’s no blue pigment in blue eyes; it’s brown pigment but the structure of the iris causes Tyndall scattering that makes them appear blue (similar to the Rayleigh scattering that makes our sky appear blue).
So this question is kind of like saying “my cities tallest building looks very different from Sears tower and the Burj Khalifa, it is different just because of the cement used?”
The answer is yes and no. The differences in genetics are expressed as proteins. There is no other way that different genes make people look differently.
The interesting part of genetics is epigenetics, which can involve changes made over many generations; and the environmental effect on genetics, one of my favorite example of this is people’s response to stress over many years of life: it is determined by their genes, their environment at the time, and their personal actions to cope.
Yes, the differences you see in people is based on proteins that are coded for in genes, but it’s more complicated since not everyone has the same response to the same genes, this is why people are able to see the differences between identical twins. They have the same genes, but they appear and act slightly different