Why is the White-eyed characteristic more common in males?
Because the white-eye allele is recessive, a female will have white eyes only if she has the white-eye allele on both her X chromosomes. However, in males, a single copy of the white-eye allele on the lone X chromosome will lead to white eyes because no other allele is present.
Can female flies have white eyes?
All of the females and all of the males will have red eyes. All of the females will have white eyes; half of the males will have red eyes, and half of the males will have white eyes.
Why do some flies have white eyes?
They have a defect in their “white” gene, which normally produces the red pigments in the eye. In these flies, the white gene only works partially, producing fewer red pigments than it should. These flies have white eyes.
What gene is mutated in the white-eyed flies?
Drosophila gene w
What is the genotype for a purebred fly with white eyes?
EE
What Colour are the eyes of an RR fly?
The cross is between a red-eyed fruit fly and a white-eyed (rr) fruit fly. The only way an offspring can have white eyes, is if it inherited a recessive allele from both parents. The gene for eye color in fruit flies is actually sex-linked on the X-chromosome.
What is the probability that their offspring will have white eyes?
50%
What are the phenotypic ratios of a white-eyed female is crossed with a red-eyed male?
When white-eyed males are crossed with red-eyed females, all the F1 progeny have red eyes, showing that the allele for white is recessive. Crossing the red-eyed F1 males and females produces a 3:1 F2 ratio of red-eyed to white-eyed flies, but all the white-eyed flies are males.
Do white eyed males inherit the allele for white eyes from their father or their mother?
50% will inherit the white allele from mother and have white eyes.
Is white eyed Drosophila recessive?
The eye color gene is located on the X chromosome (one of the sex determining chromosomes of Drosophila). White eye color is recessive. Therefore, there can be no red-eyed males in the first generation, but they will appear in the second and later generations.
What is the genotype of a white eyed female fly?
Genotypes and phenotypes of offspring if the female is heterozygous. Half of the male and half of the female offspring of a heterozygous female would be white-eyed; the other half would be red-eyed. Therefore the female must be a heterozygous, Xw+ Xw.
What is the genotype for a white eyed male?
The male is hemizygous for both the recessive (white) eye color allele and dominant (tan) body color allele. His genotype is Xwy+ Y.
Why are females not considered Hemizygous?
Because females have two copies of the X chromosome, whereas males have only one (they are hemizygous), diseases caused by genes on the X chromosome, most of which are X-linked recessive, predominantly affect males.
Is female Homogametic?
In many species, including humans, the male is heterogametic and carries an X and Y sex chromosome while females are homogametic and carry two copies of the X chromosome.
Are human males Hemizygous?
Males are said to be “hemizygous” for any X-chromosome genes, meaning that there are only half (“hemi”) as many alleles as normally present for a diploid individual. As a consequence, if males (but not females) inherit an X-linked recessive trait from their mothers, they display the recessive phenotype.
Can a man be heterozygous?
Males are typically XY, meaning that they would have to obtain their X chromosome from their mother. They can never be heterozygous as the colour-blindedness is sex-linked; i.e. the X chromosome determines whether you’ll get the disorder or not.
What is the difference between hemizygous and heterozygous?
Homozygous describes a genotype consisting of two identical alleles at a given locus, heterozygous describes a genotype consisting of two different alleles at a locus, hemizygous describes a genotype consisting of only a single copy of a particular gene in an otherwise diploid organism, and nullizygous refers to an …