Although the first generation of 1,237 offspring was all red-eyed but for three, white-eyed flies appeared in larger numbers in the second generation. Surprisingly, all white-eyed flies were
male
.
Why were all the white-eyed flies male?
Most of the white-eyed flies were male. … Morgan hypothesized that, in his breeding experiment, the first generation of flies contained males only with white eyes
because the gene controlling eye color was on the X chromosome
. Males displayed the white eye trait because the trait was present on their only X chromosome.
Are white-eyed fruit flies male?
white, abbreviated w, was the first sex-linked mutation discovered, found in the fruit fly Drosophila melanogaster. In 1910 Thomas Hunt Morgan and Lilian Vaughan Morgan collected a single male white-eyed mutant from a population of Drosophila melanogaster fruit flies, which usually have dark brick red compound eyes.
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.
What color eyes do female flies have?
With regard to Drosophila eye color, when the P
0
male expresses the white-eye phenotype and the female is
homozygous red-eyed
, all members of the F
1
generation exhibit red eyes.
Why do 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?
The Drosophila gene w (CG2759)
is a central part of the eye-pigmentation pathway. It encodes an ATP binding cassette transporter, White (O’Hare et al., 1984; Pepling and Mount, 1990), that forms dimers with either Brown or Scarlet proteins, encoded by brown and scarlet genes respectively.
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.
Are white eyes in fruit flies dominant?
The eye color gene is located on the X chromosome (one of the sex determining chromosomes of Drosophila).
White eye color is recessive
.
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 does a female fruit fly need for 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.
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 is the first greatest discovery of genetics?
04:09 Bill Nye: With this insight Mendel made the first great discovery in the science of genetics:
Each inherited characteristic must be decided by a pair
of, what he called, factors. Each parent, he said, contributes one factor for each characteristic.
How can you tell if a fly is male or female?
Sexing flies
The most simple characteristic to use to differentiate the two is to
look at the genitalia of the flies
. Males have dark, rounded genitalia at the tip of their abdomen, whereas females have light, pointed genitalia.
Can fruit flies have black eyes?
These flies are very small, about 1/8 inch long, and with dark brown to black bodies and very dark colored eyes. Lighter colored spots over the thorax create a “freckled” appearance. They are slightly larger than the common vinegar flies with red eyes.
Which eye Colour is dominant in Drosophila?
In Drosophila, white eye colour is recessive X-linked trait while
red eye colour
is dominant.
