Pedigree
KEY:
Black Fill- Has the disease
White Fill- Does not have or carry the disease
Fill With Black Dot- Carrier of the disease
XMXM- Female that does not have or carry the disease
XMXm- Female that carries the disease
XmXm- Female that has the disease
XMY- Male that does not have the disease
XmY- Male that has the disease
ANALYSIS:
Based on the pedigree, Lori Scott, Stacy Lewis, and Donna Lewis are all carriers for the disease. John has the disease. Everyone else is normal. Lori Scott passed the trait down to John and Stacy. Since Stacy has the trait, it is possible for her to pass it down to her children. This is seen in the fact that Donna is also a carrier. If Donna were to pass the trait down to one of her sons, he would automatically get the disease. This is because the disease is a sex linked disease, which means that the bad trait can only be carried in the X chromosome. Since females have two X chromosomes, they need both to carry the bad trait due to it being recessive. Males only have one X chromosome, so they only need one bad chromosome to be passed down in order to have the disease.
Black Fill- Has the disease
White Fill- Does not have or carry the disease
Fill With Black Dot- Carrier of the disease
XMXM- Female that does not have or carry the disease
XMXm- Female that carries the disease
XmXm- Female that has the disease
XMY- Male that does not have the disease
XmY- Male that has the disease
ANALYSIS:
Based on the pedigree, Lori Scott, Stacy Lewis, and Donna Lewis are all carriers for the disease. John has the disease. Everyone else is normal. Lori Scott passed the trait down to John and Stacy. Since Stacy has the trait, it is possible for her to pass it down to her children. This is seen in the fact that Donna is also a carrier. If Donna were to pass the trait down to one of her sons, he would automatically get the disease. This is because the disease is a sex linked disease, which means that the bad trait can only be carried in the X chromosome. Since females have two X chromosomes, they need both to carry the bad trait due to it being recessive. Males only have one X chromosome, so they only need one bad chromosome to be passed down in order to have the disease.