9 upvotes, 1 direct replies (showing 1)
View submission: How do genes get passed down?
Hopefully a biologist that specializes in developmental biology and cell signaling can answer, but essentially "genes" are just coding regions of DNA that spit out protein. Those can have various functions, like for structure, or for function.
People with lactose intolerance aren't producing the protein that forms the enzyme lactase, which can breakdown lactose.
In terms of granularity, it's down to the cellular level, as that's where everything happens.
The shape of your nose is determined by your bone cells and how they form/destroy bone based on the instructions in your DNA.
Your cells have chemical signals they release that tell their neighbours what they're doing and certain genes are turned on or off depending where the cell is in the body. This information would be stored in your developmental genes.
An example would be that human embryos develop gills, as we still have the instructions for gills from when we were fish, but those skin flaps are quickly sealed up as those genes are turned off in no time.
Inheritance not only applies to genes, but also to non-coding regions of your DNA, what we used to call "junk DNA". Today its called the epigenome, meaning above the genome.
You have promoter regions upstream from your genes, as well as assistant proteins that help with gene expression.
Your DNA is also packaged by being wrapped around histones, like beads on a string or knots. Environmental factors can influence how tightly your DNA is wrapped - if its in its open form, euchromatin, the gene can be expressed. If it's wound tightly and physically closed off, as heterochromatin, the gene is silenced.
https://en.wikipedia.org/wiki/Euchromatin
Histone modification is heritable, and is one of the factors responsible for gene penetrance - just because you have a gene, doesn't mean its a 100% chance you express it.
https://en.wikipedia.org/wiki/Penetrance#Epigenetic_regulation
It's also responsible for gene expressivity - how intense is the trait?
https://en.wikipedia.org/wiki/Expressivity_(genetics[1])
1: https://en.wikipedia.org/wiki/Expressivity_(genetics
Comment by jombozeuseseses at 24/11/2024 at 00:21 UTC*
9 upvotes, 0 direct replies
Non-coding regions and epigenetics are two different concepts! The former are regions in the genetic sequence which does not appear to actually transcribe into anything but play crucial roles in gene expression, whereas epigenetics are chemical modifications of any part of your genes. For example, you can have methylation of both exons and introns, but exons tend to methylate more.