Colorblindness

Colorblindness is a recessive allele, also being a hereditary gene.  It is vastly more likely that a male will be colorblind than a female.  This imbalance is caused by X and Y chromosomes.  X and Y chromosomes are what determine a person’s gender.  Females always have two X chromosomes, males always have X and Y chromosomes.  What gender a baby will be is based on the father’s factor.  He will either give an X or a Y chromosome to the egg.  If it is an X chromosome then the baby will be a female.  If it is a Y, the baby will be a male.

The above information is the basis on which the continuing will follow.  Why are males far more likely to inherit colorblindness?  To answer this, we will use an example.

The mother is heterozygous for colorblindness, which means she has normal vision, but she is a carrier for the allele.  The father is homozygous for normal vision, which means he has normal vision, but doesn’t carry the allele.  All their male offspring will have a 50% chance of inheriting colorblindness.

This is because the Y chromosome can’t mask colorblindness with another allele.  But if a daughter got the allele for colorblindness, she probably would be normal-visioned because her other X chromosome would mask it with a dominant allele for normal sight.  (Alleles are genes that are recessive or dominant.  The allele for colorblindness is recessive, which means that an allele for normal vision will mask it.)

The only way for a daughter to inherit colorblindness would depend on the circumstance of the father being colorblind and the mother being heterozygous for colorblindness or colorblind herself.

 

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