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Sex linkage in fruit flies and huntingdons disease

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Introduction

In fruit flies the eye colour trait is determined by the sex chromosome. There are two sex chromosomes, X and Y; XX indicates the individual is a female and the XY indicates being male. The sex chromosome include other genes that determine other traits. When these genes are positioned on a sex chromosome, they are named as sex-linked genes. The eye colour gene for fruit flies are solely found on the X chromosome because it is much bigger in size when compared to the Y chromosome; therefore, the genetic information found on the X chromosome is much more than the Y chromosome. As female flies have a double copy of the eye colour gene, one on each of the X chromosome and male flies have one copy of the eye colour gene on the X chromosome, therefore that one copy gene will show up whichever allele he inherits from the mother flies. ...read more.

Middle

and 25% have red eyes (XRY-); 25% of female offsprings have white eyes (XrXr) and 25% have red eyes (XRXr). As the males can inherit only one eye colour allele, which is from the mother and she had both dominant (XR) and recessive (Xr) eye colour alleles, 50% showed up as white eye colour and 50% showed up as red eye colour. Whereas the females inherit both alleles, one from the mother and one from the father. In all cases the father passed down the recessive allele (Xr) and the mother passed down the dominant (XR) and recessive (Xr). 50% of the females are all carriers and their eye colour shows up as red, due to the mother passing down her (XR) allele and the father passing down his (Xr) allele. The rest of the females have white eyes due to the father passing down his (Xr) ...read more.

Conclusion

Colour blindness? most common form is named the red/green colour blindness. Red/green colour blindness sufferers mix up all the colours that have some red and/or green as part of the entire colour. For example they will see pink as white as they view red colour component is separated from the pink. According to the punnet square results only 25% of the offspring?s will have neither of the disorders and 75% will have at least one of them. Therefore, if the couple want to have a child of their own it is a risk worth taking. Their other option is to have In Vitro Fertilisation (IVF) treatment done as this allows the egg and the sperm to be fertilised outside the body, this way the traits that are being passed down could be tracked and determined to give birth to a healthy child. ...read more.

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