Is sepia eyes dominant or recessive?
Sepia eyes (se, 3; 26.0) are an autosomal recessive trait on Chromosome 3 that produces a dark brown eye color.
What color are flies eyes and sex?
Thomas Hunt Morgan mapped this trait to the X chromosome in 1910. Like humans, Drosophila males have an XY chromosome pair, and females are XX. In flies, the wild-type eye color is red (XW) and it is dominant to white eye color (Xw) (Figure 1).
What is considered a sex linked trait?
A sex-linked trait is a trait that is controlled by a gene or an allele located on the sex chromosome. In humans, the sex chromosomes are the X chromosome and the Y chromosome. For example, color blindness is a sex-linked trait whose allele is recessive and located on the X chromosome.
Why do sepia colored eyes arise in fruit flies?
The fruit fly Drosophila melanogaster possesses disproportionately large, often vividly colored eyes. These range in color from red to sepia to white and indicate a great deal about the fly’s genetic makeup. Brown and sepia eyes are a result of a recessive gene and only occur when two sepia-eyed flies mate.
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.
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 can’t female fruit flies have white eyes?
Females have two X-chromosomes. The X-chromosome is larger and contains more genes than the Y-chromosome, so most sex-linked traits are X-linked traits. Wild-type fruit flies have dark red eyes, but there are recessive alleles of this eye color gene (called the white gene) that cause individuals to have white eyes.
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.
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.
Are white-eyed flies blind?
White-eyed flies are not blind; instead they are easily temporarily blinded by bright light at certain frequencies because they lack the protection provided by the red and brown pigments.
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.
How can a white-eyed female be produced?
The white-eye trait can be carried over to females when F1 females are crossed with white-eyed males.
What was the gender of all of the white-eyed flies?
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.
What is the chance that the female offspring will be white-eyed?
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.
What is the genotype for a purebred fly with white eyes?
EE
What Colour are the eyes of an RR fly?
white
What is the probability of getting offspring that are red-eyed males?
25%
What is the genotype of a white eye female fly?
The result of the cross was that half of the male and half of the female offspring were red-eyed, and half of the male and half of the female offspring were white-eyed. What was the genotype of the female fly? The female fly had to be heterozygous, Xw+ Xw.
Can a female be Hemizygous?
Only one X chromosome is present in males . So only single recessive allele is enough to express the character in male . This condition is called as hemizygous condition . Female is showing homozygous dominant or recessive or heterozygous dominant but not hemizygous condition .
Is eye Colour monogenic?
In humans, the most remarkable eye color diversity is found among Caucasians. Blue/brown eye color genetics are known to the public as school example of monogenic inheritance, however, the variation in pigment concentration and the distribution of pigment in the iris (Fig.