Monday, May 10, 2010

What happens when a gene is present in one parent and not in another?

I am not referring to different gene variants, or alleles, but


a situation where one gene is on the chromosome of the


father but not on the corresponding one for the mother.





Say you have AA on the father but 00 (nothing) on the mother





is the result for the offspring: A0,A0,A0,A0 = 0 ?





What happens in that situation?





Does the father's gene get passed onto the offspring?What happens when a gene is present in one parent and not in another?
All the offspring will be A0. The father's gene is passed on. Depending on the significance of the gene, individuals may be able to live without a copy. If the gene is deleterious (for example, the target of a toxin in a food source), individuals without the gene may fare better. A notable condition in which this occurs is 伪-thalassemia. There normal human genome has two tandem copies of the 伪-globin chain of hemoglobin, or four copies, total. There are variant chromosomes with one or zero copies.





The null allele is usually indicated with a dash.What happens when a gene is present in one parent and not in another?
I think your answer can vary.


An example is:


Say the father has Blue eyes which are dominant he is represented as say BB


or he could be Bb where he has blue eyes but also carries the gene for say brown eyes.


Say the mother has brown eyes which is represented as bb (and as you mentioned does not carry the blue eyed gene at all so she can't be Bb)





Therefore the offspring depending on whether the father has dominant blue eyes (BB) or recessive blue eyes (Bb) will determine the outcome of the offspring.


All offspring may all by blue eyed (if father is BB) but carry the recessive gene of the mother (Bb) or;


The offspring may be 1:1 with half the children being Bb (and have blue eyes) or bb (with brown eyes)
It will, but it won't be shown in the offspring.


Like, if AA is blond hair (Dominant) , and oo is Brown hair (Recessive), all the offspring will have Blond hair, but they will carry the brown hair gene, which, if they marry a brown haired girl, there is no chance the offspring will have blond hair.


I think.
Depends on which is recesive and which is active.
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