Monohybrid Sex-linked?

In humans, color vision is X-linked' the gene for color vision is located on the X chromosome but is absent from the Y chromosome. Normal color vision (XN) is dominant over color blindness (Xn). A color blind man fathers the children of a woman with the genotype XNXN


What genotype is the father?


What proportion of daughters will be color-blind?


What proportion of sons will be color blind?





Now one of these daughters marries a color-blind man.


What are the chances that their sons will be color blind?


Explain how a color blind daugher might result from this


couple?

Monohybrid Sex-linked?
The father is Xn Y0 (Y is anything since it doesn't carry the color blind gene.


Do a punett square of father and mother


______ XN | XN


Xn | XNXn | XNXn


Y0 | XNY0 | XNY0





None of the children daughters or sons will be colorblind.





Daughter genotype XNXn (she's a carrier of color blindness)


Blind man genotype XnY0


another punett square


____ XN | Xn


Xn | XNXn | XnXn


Y0 | XNY0 | XnY0


half the sons will be color blind.


A color blind daughter would occur if the carrier gene from the mother happened to be passed on. Since the only X chromosome the father has contains the color blind gene she woul get two Xn chromosomes resulting in color blindness.


Hope this has helped