1. In fruit flies, the gene for white eyes is sex-linked recessive. (R) is red and (r) is white. Cross a white- eyed female with a normal red-eyed male.
What is the genotype of the female fruit fly?
Possible female genotypes
Since the female fly has a yellow body, and the tan body color is the dominant allele, she will be homozygous recessive for yellow body color. Therefore, the female fly will be homozygous for both traits. The genotype is X w + y X w + y .
What is the genotype for a white eyed female fruit 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, X w+ X w .
Can female fruit 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.
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 X wy+ Y .
Which of the following is are required for a female fruit fly to be born with white eyes?
1. In fruit flies, the gene for white eyes is sex-linked recessive . (R) is red and (r) is white. Cross a white- eyed female with a normal red-eyed male.
What is the chance that the offspring will have white eyes?
What is the chance that there will be an offspring with white eyes? 50% or 244 Page 2 6. Hemophilia is a disease caused by a gene found on the X chromosome. Therefore, it is referred to as a sex-linked disease.
Why do some fruit 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.
Can a female be Hemizygous?
Females are XX . Males are XY. Since males have only a single copy of the X chromosome, they have only a single allele for any gene on the X chromosome. 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.
What is the genotype of a red eyed female fruit fly?
In females, the presence of one dominant red encoding allele (X W ) will produce red eyes even if the individual is heterozygous for the white allele. Females can be: Homozygous dominant for the red encoding allele – genotype: X W X W ; phenotype: red eyes.
Why are white eyed female fruit flies so rare in nature?
White eyes are very rare in natural fruit fly populations. ... Morgan realized that in these flies, eye color must somehow be tied to sex . From this and other evidence, Morgan deduced that the gene involved in this inheritance pattern is located only on the X chromosome. There is no corresponding eye color locus on the Y.
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.
How can a white eyed female be produced?
The white-eye trait can be carried over to females when F 1 females are crossed with white-eyed males .
What percent of males will have red eyes?
probability of getting red-eyed males? (You must include the probability of getting males AND red eyes). Step 5: One out of four ( 25% of) offspring will be both inale, and have red eyes.
What is the most likely mode of inheritance?
The most likely mode of inheritance is therefore X-linked recessive .
Is PP genotype or phenotype?
A simple example to illustrate genotype as distinct from phenotype is the flower colour in pea plants (see Gregor Mendel). There are three available genotypes, PP ( homozygous dominant ), Pp (heterozygous), and pp (homozygous recessive).
