Homozygous dominant for the red encoding allele – genotype: XWXW ; phenotype: red eyes. Heterozygous – genotype XWXw; phenotype: red eyes. Homozygous recessive with two white encoding alleles – genotype XwXw; phenotype white eyes.
What is the genotype of the white-eyed male fly?
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). Drosophila males lack a second allele copy on the Y chromosome; that is, their genotype can only be XWY or XwY .
What is the genotype of a male fly?
The sex of the fruit fly Drosophila melanogaster is determined as follows: XX chromosomes give a female and XY give a male. The gene for bar eyes is recessive and located on the X chromosome. A male has a genotype RrTt .
What is the genotypic ratio of red eyed fruit fly?
| Genotypic Ratio Phenotypic Ratio | 1⁄2 X R X r 1⁄2 X R Y 1⁄2 red eyed female 1/2 red eyed male |
|---|
What is the genotype for a red eyed female fruit fly?
What is the genotype of a red-eyed, yellow-bodied female fruit fly who is homozygous for the eye color allele? Red eyes (w+) and tan bodies (y+) are the dominant alleles. (Both traits are X chromosome linked).
What is a mutant trait?
mutant An individual having a phenotype that differs from the normal phenotype .
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.
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.
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).
What is the genotype of a female fly with white eyes?
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 .
Is red eyes in flies dominant or recessive?
In flies, the wild-type eye color is red (X W ) and it is dominant to white eye color (X w ) (Figure 1). Because of the location of the eye-color gene, reciprocal crosses do not produce the same offspring ratios. Males are said to be hemizygous, because they have only one allele for any X-linked characteristic.
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.
Why did Hunt Morgan use fruit flies?
Thomas Hunt Morgan, an embryologist who had turned to research in heredity, in 1907 began to extensively breed the common fruit fly, Drosophila melanogaster. He hoped to discover large-scale mutations that would represent the emergence of new species. ... He isolated this specimen and mated it to an ordinary red-eyed fly.
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.
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 percentage of the kittens will be orange and female?
Only about 1 in 5 orange tabby cats is female .
Scientists and researchers are fairly certain that orange tabbies' color transpires from a sex-linked gene, with the X chromosome responsible for the orange coloring.
