Codominance

[spherelin]

Hey,

Can someone please give me an accurate and simple definition of co-dominance?

Thanks

[duquesne9995]

mode of inheritance where both alleles in the heterozygote are equally and fully expressed

[spherelin]

mode of inheritance where both alleles in the heterozygote are equally and fully expressed

Thanks for that, just another thing, do we need to know about polymorphism? I came across a full question on it in the STAV 2009 paper!

[aishuwa1995]

Thanks for that, just another thing, do we need to know about polymorphism? I came across a full question on it in the STAV 2009 paper!

Since it's related to genetic variation I think so..(human blood group is an example of polymorphism right?)

[spherelin]

Thanks for that, just another thing, do we need to know about polymorphism? I came across a full question on it in the STAV 2009 paper!

Since it's related to genetic variation I think so..(human blood group is an example of polymorphism right?)

I have no idea  do you use TSFX (exam lecture), A+ or STUDYON notes? If so, can you please direct me to what page all the info is on? I've been searching for this topic or ages... and failed to find it haha.
OH! and also, isn't the human blood group an example of co dominance? D:

[aishuwa1995]

Thanks for that, just another thing, do we need to know about polymorphism? I came across a full question on it in the STAV 2009 paper!

Since it's related to genetic variation I think so..(human blood group is an example of polymorphism right?)

I have no idea  do you use TSFX (exam lecture), A+ or STUDYON notes? If so, can you please direct me to what page all the info is on? I've been searching for this topic or ages... and failed to find it haha.
OH! and also, isn't the human blood group an example of co dominance? D:

No I don't use other notes or revision guides, I just read the text book and the powerpoints from my school..sorry 
I googled polymorphism just then and wikipedia agrees with me  blood group is a polymorphic trait
http://en.wikipedia.org/wiki/Polymorphism_(biology)
Blood type does show co dominance and it's also an example of multiple allele inheritance..I agree, this can be confusing 

[spherelin]

Thanks for that, just another thing, do we need to know about polymorphism? I came across a full question on it in the STAV 2009 paper!

Since it's related to genetic variation I think so..(human blood group is an example of polymorphism right?)

I have no idea  do you use TSFX (exam lecture), A+ or STUDYON notes? If so, can you please direct me to what page all the info is on? I've been searching for this topic or ages... and failed to find it haha.
OH! and also, isn't the human blood group an example of co dominance? D:

No I don't use other notes or revision guides, I just read the text book and the powerpoints from my school..sorry 
I googled polymorphism just then and wikipedia agrees with me  blood group is a polymorphic trait
http://en.wikipedia.org/wiki/Polymorphism_(biology)
Blood type does show co dominance and it's also an example of multiple allele inheritance..I agree, this can be confusing 

Okay, that is so confusing! haha but thanks

[aishuwa1995]

Thanks for that, just another thing, do we need to know about polymorphism? I came across a full question on it in the STAV 2009 paper!

Since it's related to genetic variation I think so..(human blood group is an example of polymorphism right?)

I have no idea  do you use TSFX (exam lecture), A+ or STUDYON notes? If so, can you please direct me to what page all the info is on? I've been searching for this topic or ages... and failed to find it haha.
OH! and also, isn't the human blood group an example of co dominance? D:

No I don't use other notes or revision guides, I just read the text book and the powerpoints from my school..sorry 
I googled polymorphism just then and wikipedia agrees with me  blood group is a polymorphic trait
http://en.wikipedia.org/wiki/Polymorphism_(biology)
Blood type does show co dominance and it's also an example of multiple allele inheritance..I agree, this can be confusing 

Okay, that is so confusing! haha but thanks

terribly sorry if I confused you

[duquesne9995]

thiskid, you're right. Blood group is multiple allele inheritance because at the gene loci for antigens on red blood cells, there is the I^A allele, the I^B allele and the i allele.
Then blood group is an example of co-dominance because the heterozygote with genotype I^A I^B fully and equally expresses both alleles so that they have the A and B antigens on their red blood cells.
And then it is an example of polymorphism because there is more than one variation/phenotype of this trait in the population i.e. there are individuals who are blood group A, B, O, AB.
Spherelin do you use nature of biology textbook? Chapter 13. 

[spherelin]

thiskid, you're right. Blood group is multiple allele inheritance because at the gene loci for antigens on red blood cells, there is the I^A allele, the I^B allele and the i allele.
Then blood group is an example of co-dominance because the heterozygote with genotype I^A I^B fully and equally expresses both alleles so that they have the A and B antigens on their red blood cells.
And then it is an example of polymorphism because there is more than one variation/phenotype of this trait in the population i.e. there are individuals who are blood group A, B, O, AB.
Spherelin do you use nature of biology textbook? Chapter 13. 

I think i get it now. So does this kind of mean that polymorphism is derived from co-dominance?

[duquesne9995]

Well I wouldn't say it is derived from co-dominance. It can happen with simple dominant/recessive inheritance or incomplete dominance etc. It is just when there is more than one variation/phenotype of the trait in the population.

[spherelin]

Well I wouldn't say it is derived from co-dominance. It can happen with simple dominant/recessive inheritance or incomplete dominance etc. It is just when there is more than one variation/phenotype of the trait in the population.

isn't that like continuous variation though? I feel super dumb at the moment! hahahahaha where would i be without atarnotes

[Scooby]

Well I wouldn't say it is derived from co-dominance. It can happen with simple dominant/recessive inheritance or incomplete dominance etc. It is just when there is more than one variation/phenotype of the trait in the population.

isn't that like continuous variation though? I feel super dumb at the moment! hahahahaha where would i be without atarnotes

A polymorphic population has members that display more than one variant of a particular phenotype. However, that doesn't mean that variation in that phenotype is continuous - it could also be discontinuous. Continuous/discontinuous variation refers more to whether we can place these variants of a phenotype into distinct groups, rather than how many variants there actually are.

Human populations are polymorphic with regard to the ABO blood group. People can have blood type A, B, AB or O. Even though there are four possible phenotypes, this variation is still considered discontinuous, since each variant can be clearly distinguished from the others. You're either blood type O or you're not, you can't just have a bit of it.

Generally though, the greater the number of variants in a particular phenotype, the more likely that this variation is continuous, rather than discontinuous

[aishuwa1995]

thiskid, you're right.

Oh good..at least I have the right idea

Well I wouldn't say it is derived from co-dominance. It can happen with simple dominant/recessive inheritance or incomplete dominance etc. It is just when there is more than one variation/phenotype of the trait in the population.

isn't that like continuous variation though? I feel super dumb at the moment! hahahahaha where would i be without atarnotes

It is kind of similar but it's not the same....
Polymorphism is literally the existence of "many forms" in a population and it involves both discontinuous and continuous variation.
This might be useful to explain what I mean with discontinuous and continuous variation http://www.biologymad.com/resources/RevisionM5Ch2.pdf

EDIT: What Scooby said.

[Jenny_2108]

http://www.biologymad.com/resources/RevisionM5Ch2.pdf

this link is so useful kidddddddd!!!!!!!
Omg, they have standard deviation as well, feel like studying normal distribution in maths