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Title: Cross a red eye male with a white eyed female. Show the genotypes and phenotype. Post by: Courtney22132 on Mar 11, 2014 The colour of eyes in fruit flies is determined by a gene on the X chromosome with two alleles.
XR= Red eyes. Xr= white eyes. Cross a red eye male with a white eyed female. Show the genotypes and phenotypes, including the sex, of the parents and offspring… Very lost on this one! It's for 5 marks and I'm a bit confused. Thanks! Title: Re: Cross a red eye male with a white eyed female. Show the genotypes and phenotype. Post by: Alexx on Mar 11, 2014 Red eyed males are XR Y while white eyed females are Xr Xr. (If you don't understand why, just ask.)
Male offsprings will inherit a Y allele from "father" and a Xr from "mother". So all male offsprings are Xr Y, meaning they are all white eyed. Female offsprings will inherit a XR from father and a Xr from mother, meaning they will all be red eyed. (XR Xr) Crossing: Male XR Y female Xr Xr Offsprings XR Xr / Xr Y (50% / 50%) (offsprings with Y are males) |