Can monosomy and trisomy...

[Guest kay_trudo]

Can monosomy and trisomy be present in the same zygote so that they compliment each other, for example if one of the gametes had a monosomy and the other had trisomy, and they were both for the same pair of chromosomes could they chancel each other out?

[Radical Edward]

so instead of having a chromosome from the mother and father, you just get both from one parent, right? I don't see why not, though you wouldn't have a gamete with trisomy (since that would be 3 chromosomes in the gamete). The problem I see though is imprinting.

[admiral_ju00]

so instead of having a chromosome from the mother and father, you just get both from one parent, right? I don't see why not, though you wouldn't have a gamete with trisomy (since that would be 3 chromosomes in the gamete). The problem I see though is imprinting.

 

yep, this will give you a condition what is called mental retardation or a more politically correct version: the Down syndrome but there's a number of others you can get, depending which chromosome or alleles you've got an extra copy of.

 

you get 2 from one parent, plus one more from the other parent............

and no, they won't cancel each other out, you'll just have extra things that you shouldn't, and for a very good reason too.

the thing is, there are a handful of such occurances that can happen and the embryo will develop into a fetus, fetus into a child, etc. and this can happen on very few, select chromosomes where you can get more than 1 chromosome. granted, should an embryo fail to abort itself shorty after meosis, he/she will have various physiological or psychological problems.

most other such chromosomal mutations or segregation failures are fatal to the zygote and it will self abort.

[Radical Edward]

downs syndome is specifically Trisomy 21. different trisomies have different names, for example trisomy 18 is Edward's Syndrome. others like Trisomy 1 and 2 don't even survive, except in mosaicism.

[admiral_ju00]

downs syndome is specifically Trisomy 21. different trisomies have different names, for example trisomy 18 is Edward's Syndrome. others like Trisomy 1 and 2 don't even survive, except in mosaicism.

 

yes, i'm very well aware of that. are you aiming this at me, if so, then you're just contradicting yourself from your original reply #2

[Radical Edward]

yes, i'm very well aware of that. are you aiming this at me, if so, then you're just contradicting yourself from your original reply #2

 

it sounded like you were saying all trisomies were chromosome 21. and how am I contradicting #2?

[admiral_ju00]

so instead of having a chromosome from the mother and father, you just get both from one parent, right? I don't see why not

 

The 'I don't see why not' is not very reassuring

 

though you wouldn't have a gamete with trisomy (since that would be 3 chromosomes in the gamete).

 

Yes you can. I can't readily recall the names of conditions(but names aren't really relevant at this point since we're not trying to diagnose a condition merely establish some 'base' facts), but you can have an offspring with any of the following chromosomal distributions:

Let's take the sex chromosomes for example:

 

XX / XY - Normal

X_ /Y_ -Abnormal

XXX / XXY - Abnormal

XXXX/ XXXY / XXYY - Abnormal

[Radical Edward]

The 'I don't see why not' is not very reassuring

well nothing I know of suggests that there is anything wrong with inheriting both chromosomes from one parent' date=' though I did mention imprinting, and that could be a problem.

Yes you can. I can't readily recall the names of conditions(but names aren't really relevant at this point since we're not trying to diagnose a condition merely establish some 'base' facts), but you can have an offspring with any of the following chromosomal distributions:

Let's take the sex chromosomes for example:

 

XX / XY - Normal

X_ /Y_ -Abnormal

XXX / XXY - Abnormal

XXXX/ XXXY / XXYY - Abnormal

 

I know about those. come to think of it though, I am rather confused by the opening post. Essentially it asks if monosomy and trisomy can exist in the same zygote and cancel one another out. That would be a chimera.

 

add to that, but gametes don't get "monosomy", they are haploid by default, unless something is wrong with them.

 

so the opening question sounds like if we have a gamete with A and a gamete with AAA, will it be normal, and the anwer is no, because that would produce a zygote with AAAA. however, imprinting aside, if we have a gamete with O and a gamete with AA, it would be normal.

[Guest kay_trudo]

yeas thank you thats what i meant if one gamete has 0 and one have AA... but

[Guest kay_trudo]

yeas thank you thats what i meant if one gamete has 0 and one have AA... but

 

forget the "but" that was a typo

[Radical Edward]

you can edit posts, it's just next to the quote button in the bottom right of your message

 

thanks for clearing that up for us I think the main problem would be imprinting - this is a process where certain genes are marked, purely by virtue of which parent it comes from. There are a number of imprinting genes that we know of, for example the males imprint the genes for as much growth as possible in the foetus - big babies have a higher chance of surviving, so it is better for the father to sire large children, however it is detrimental to the mother, as it affects her health and means she requires alot more resources to feed her growing child, so the mother tries to limit the growth of the foetus. If the father does not imprint that gene, then the babies tend to be born significantly smaller (as has been demonstrated in mice) and if the mother does not imprint her gene, the babies are born much larger. Other examples are of aggressiveness, seen in Turner Syndrome girls (X0) - if the X comes from the father, the girls act more feminine, if the X comes from the mother, the girls are more agressive.