So, say I get a set of chromosomes from my Mum which contains the X chromosome and the same from my Dad, but with the Y chromosome. I now have two sets of the same 22 chromosomes, plus an X and a Y.
For chromosome number one for example, is everything from my Dad’s side activated? My Mum’s? Or is is a random selection of genes within each chromosome?
And does the X chromosome do anything for me, or is it turned off, and only used if I pass it on to the next generation?
Follow up question: I believe that women actually recombine their X chromosomes when passing these on, but men can’t recombine X and Y. So everything on your Dad’s side stays the same. Does this have any impact? For example are you more likely to inherit genetic defects from your Dad’s side?
Some genes are dominant and some are recessive. Dominant genes override recessive genes regardless of which parent it’s inherited from. Some genes that simply aren’t compatible with each other are altered during fertilization. These altered genes are called mutations. Some are beneficial, some are harmful, but most are benign. Some genes only come from the Mother, which would be the genes for the mitochondria. While some will only come from the father, which would be the genes for the nucleus.
As for X and Y chromosomes. The X chromosome contains a lot of info you need in order to live while the Y chromosome just codes for what makes a being male. If you have a defective gene in your X chromosome and are male, chances are that it’s going to present itself. If you’re female, it depends on if that gene is dominant. One notable case is the genes for the cones in your eyes. They reside in the X chromosome and sometimes one of those genes has mutated. If you only have the mutated version you may be unable to see some colors. As [email protected] pointed out, this has advantages and disadvantages.
Disclaimer: I’m going by what I remember from high school biology. If I made an error, then please correct me.
EDIT: Corrected my wording in regards to colorblindness.
They reside in the X chromosome and sometimes one is defective or missing. That’s why color blindness is more common in males.
Yeah. That’s a little out of date.
Colorblindness isn’t worse vision, just different.
You got more rods for the missing cones, it’s not just blank space.
That helps lowlight vision, and the colorblind are also better at differentiating shades of brown.
Like, my dad was colorblind, and he could spot a deer in the woods from like a mile away. To him it was completely obvious and he never got why other people couldn’t see the deer.
I didn’t mean to imply it was bad. I’ll reword my comment.
Everyone is talking about dominant and recessive genes, so I just want to clarify a couple things.
The way your body directly uses genes is as a blueprint to construct proteins. Your cells are always producing proteins from the genes in all your chromosomes. It has complex ways of regulating how much of each it produces, but your body doesn’t care what chromosome it’s coming from. Once an embryo is fertilized, there’s really no distinction between “mom” chromosomes or “dad” chromosomes, as far as the embryo and its protein machinery are concerned.
“Dominant” and “recessive” characterization is about how those proteins affect your body at the macro scale, not whether your body actually uses the gene and produces its proteins – it always does that. For example, brown hair is a dominant trait, and blonde is recessive. But this is because producing any amount of brown pigment will make your hair brown, regardless of what other pigments you’re making, simply because it’s darker. Literally the same as combining blonde and brown paint. It has nothing to do with whether the genes are actually being expressed – the brown hair gene doesn’t stop the blonde hair gene from making its pigments.
Thank you for clarifying those misconceptions about what recessive and dominant are getting at. A gene isn’t really dominant or recessive. A phenotype (some trait in the organism like blue eyes or a certain disease) can be dominant or recessive though and results from changes in a gene. The same gene could have many different possible mutations, some with dominant effects, some with recessive effects, or some with no effects, depending on the change in the gene and the phenotype.
To go further on that, many recessive diseases are because just one functional copy of many genes are fine from your body’s perspective. Many recessive diseases are due to loss of function of a gene or its protein product, a gene that for a variety of potential reasons no longer leads to a functional protein. Often your body can get by with just one working gene making protein, though both gene copies are generally always being transcribed and trying to be turned into functional protein.
One big exception to this is the x chromosome. Males only have one x and have a y instead of a second x. The y is very tiny and has very few genes compared to the x, quite different from other chromosome pairs which generally just have copies of all the same genes on each other. Early in embryo development for xx individuals, one of the x chromosomes is generally inactivated and not expressed very much, otherwise xx individuals would have double the gene products of all those different genes compared to males, which the body is not expecting for x genes like it does for all the other genes that have a second copy.
https://en.m.wikipedia.org/wiki/X-inactivation
If you go even further you also get into the idea of penetrance. A gene codes for a protein, but that protein doesn’t exist in isolation, it interacts with lots of other proteins coded by other genes in the body, plus the environment. So for some genetic changes it might be a 100% chance at leading to a certain phenotype (like a disease or a specific trait), or it could be less, like only 70% or 30% chance or something of someone with that change getting that trait, even if it’s still “dominant” (meaning only one gene copy with that change is needed to express the trait).
You get half of your chromosomes from each of your parents, so their bodies are in charge of setting which half their child will use.
Afterwards which trait will be present goes into dominant and recessive genes.
(of course this is more complicated and someone might do a better job at explaining it in depth)Some genes are lethal let’s call them :
“T” bad version and
“t” for the version that lets you live.if one of those genes is on the xx // xy chromosomes then if you are XX female you will get one combination in this set of combinations : Tt, tT, TT, tt
if you get TT, you are dead.
if you get tt, you live,
if you get Tt or tT you have 3 possible outcomes :
if T is dominant you are dead,
if t is dominant you live,
if T and t are co_dominant you might be sick.if you are XY male, you have either a “T” (dead) or a “t” (alive).
No Child Left Behind, eh?
