Concept explainers
In Drosophila, the autosomal recessive brown eye color mutation displays interactions with both the X-linked recessive vermilion mutation and the autosomal recessive scarlet mutation. Flies homozygous for brown and simultaneously hemizygous or homozygous for vermilion have white eyes. Flies simultaneously homozygous for both the brown and scarlet mutations also have white eyes. Predict the F1 and F2 progeny of crossing the following true-breeding parents:
a. vermilion females × brown males
b. brown females × vermilion males
c. scarlet females × brown males
d. brown females × scarlet males
To determine:
The F1 and F2 progeny from the cross between vermilion females and brown males
Introduction:
The genes are the sequence of nucleotides that are present on the chromosomes and encode for a specific protein that plays a crucial role in the functioning of the different processes in an organism. The gene is located at specific gene loci and can be structural or regulatory in nature.
Explanation of Solution
The allele for vermillion trait can be expressed as (XVXV) and the allele for brown trait is (EbEb). The F1 progeny from cross between vermilion females and brown males will be as follows:
Gametes | XV | XV |
Eb | XV Eb | XV Eb |
Eb | XV Eb | XV Eb |
The F2 progeny will be as follows:
Gametes | XV | Eb |
XV | XV XV | XV Eb |
Eb | XV Eb | Xb Eb |
To determine:
The F1 and F2 progeny from the cross between brown females and vermilion males
Introduction:
The genotype is the genetic constitution of the organism while the phenotype is the external characters visible in an organism. The alleles are the contrasting forms of a gene and one of them is dominant and other is recessive
Explanation of Solution
The vermillion males can be expressed as (XVY) and the brown females can be expressed as (Eb Eb). The progeny from the cross of vermilion males and brown females will be as follows:
Gametes | Eb | Eb |
XV | XV Eb | XV Xb |
Y | Eb Y | Eb Y |
The progeny obtained from the F2 cross will be
Gametes | Eb | Y |
XV | XV Eb | XVY |
Eb | Eb Eb | Eb Y |
To determine:
The F1 and F2 progeny from the cross between brown females and vermilion males
Introduction:
The dominant allele masks the expression of the recessive allele. Therefore the dominant allele is expressed in homozygous and heterozygous genotype while the recessive phenotype is only expressed under homozygous condition.
Explanation of Solution
The scarlet females can be expressed through alleles (ESES) and the brown males are expressed as (EbEb). The progeny from the cross of brown males and scarlet females will be as follows:
Gametes | Eb | Eb |
Es | Eb Es | Eb Es |
Es | Eb Es | Eb Es |
The progeny obtained from the F2 cross will be
Gametes | Es | Eb |
Eb | Eb Es | Eb Eb |
Es | Es Es | Eb Es |
To determine:
The F1 and F2 progeny from the cross between brown females and scarlet males
Introduction:
Fertilization is the process by which the male gamete, sperm, fertilize with the female gamete, ovary. The process brings about the fusion of two haploid pronuclei into a diploid zygote.
Explanation of Solution
The brown females can be seen as (EbEb) and scarlet males are represented as (ESES). The progeny from the cross of brown females and scarlet males will be as follows:
Gametes | Eb | Eb |
Es | Eb Es | Eb Es |
Es | Eb Es | Eb Es |
The progeny obtained from the F2 cross will be
Gametes | Es | Eb |
Eb | Eb Es | Eb Eb |
Es | Es Es | Eb Es |
Want to see more full solutions like this?
Chapter 4 Solutions
Genetics: From Genes to Genomes
- Human sex chromosomes are XX for females and XY for males. a. With respect to an X-linked gene, how many different types of gametes can a male produce? b. If a female is homozygous for an X-linked allele, how many different types of gametes can she produce with respect to this allele? c. If a female is heterozygous for an X-linked allele, how many different types of gametes can she produce with respect to this allele?arrow_forwardThe following X-linked recessive traits are found in fruit flies:vermilion eyes are recessive to red eyes, miniature wings are recessiveto long wings, and sable body is recessive to gray body. A cross wasmade between wild-type males with red eyes, long wings, and graybodies and females with vermilion eyes, miniature wings, and sablebodies. The heterozygous female offspring from this cross, whichhad red eyes, long wings, and gray bodies, were then crossed tomales with vermilion eyes, miniature wings, and sable bodies. Thefollowing data were obtained for the F2 generation (including bothmales and females):1320 vermilion eyes, miniature wings, sable body1346 red eyes, long wings, gray body102 vermilion eyes, miniature wings, gray body90 red eyes, long wings, sable body42 vermilion eyes, long wings, gray body48 red eyes, miniature wings, sable body2 vermilion eyes, long wings, sable body1 red eyes, miniature wings, gray bodyA. Calculate the map distances separating the three genes.B. Is…arrow_forwardThe following X-linked recessive traits are found in fruit flies:vermilion eyes are recessive to red eyes, miniature wings are recessiveto long wings, and sable body is recessive to gray body. A cross wasmade between wild-type males with red eyes, long wings, and graybodies and females with vermilion eyes, miniature wings, and sablebodies. The heterozygous female offspring from this cross, whichhad red eyes, long wings, and gray bodies, were then crossed tomales with vermilion eyes, miniature wings, and sable bodies. Thefollowing data were obtained for the F2 generation (including bothmales and females):1320 vermilion eyes, miniature wings, sable body1346 red eyes, long wings, gray body102 vermilion eyes, miniature wings, gray body90 red eyes, long wings, sable body42 vermilion eyes, long wings, gray body48 red eyes, miniature wings, sable body2 vermilion eyes, long wings, sable body1 red eyes, miniature wings, gray bodyWhat information do you know based on the question and your…arrow_forward
- The following X-linked recessive traits are found in fruit flies:vermilion eyes are recessive to red eyes, miniature wings are recessiveto long wings, and sable body is recessive to gray body. A cross wasmade between wild-type males with red eyes, long wings, and graybodies and females with vermilion eyes, miniature wings, and sablebodies. The heterozygous female offspring from this cross, whichhad red eyes, long wings, and gray bodies, were then crossed tomales with vermilion eyes, miniature wings, and sable bodies. Thefollowing data were obtained for the F2 generation (including bothmales and females):1320 vermilion eyes, miniature wings, sable body1346 red eyes, long wings, gray body102 vermilion eyes, miniature wings, gray body90 red eyes, long wings, sable body42 vermilion eyes, long wings, gray body48 red eyes, miniature wings, sable body2 vermilion eyes, long wings, sable body1 red eyes, miniature wings, gray bodyWhat topic in genetics does this question address?arrow_forwardThe following X-linked recessive traits are found in fruit flies:vermilion eyes are recessive to red eyes, miniature wings are recessiveto long wings, and sable body is recessive to gray body. A cross wasmade between wild-type males with red eyes, long wings, and graybodies and females with vermilion eyes, miniature wings, and sablebodies. The heterozygous female offspring from this cross, whichhad red eyes, long wings, and gray bodies, were then crossed tomales with vermilion eyes, miniature wings, and sable bodies. Thefollowing data were obtained for the F2 generation (including bothmales and females):1320 vermilion eyes, miniature wings, sable body1346 red eyes, long wings, gray body102 vermilion eyes, miniature wings, gray body90 red eyes, long wings, sable body42 vermilion eyes, long wings, gray body48 red eyes, miniature wings, sable body2 vermilion eyes, long wings, sable body1 red eyes, miniature wings, gray bodyAnalyze data. Make a drawing. Make a calculation.arrow_forwardIn Drosophila, the X-linked recessive mutation vermilion (v) causes bright red eyes, in contrast to the brick-red eyes of wild type. A separate autosomal recessive mutation, suppressor of vermilion (su-v), causes flies homozygous or hemizygous for v to have wildtype eyes. In the absence of vermilion alleles, su-v has no effect on eye color. Determine the F1 and F2 phenotypic ratios from a cross between a female with wild-type alleles at the vermilion locus, but who is homozygous for su-v, with a vermilion male who has wildtype alleles at the su-v locusarrow_forward
- The phenotype of vestigial (short) wings (vg) in Drosophila melanogaster is caused by a recessive mutant gene that independently assorts with a recessive gene for hairy (h) body. Assume that a cross is made between a fly that is homozygous for normal wings and has a hairy body and a fly with vestigial wings that is homozygous for normal body. The wild-type F1 flies were crossed among each other to produce 1024 F2 offspring. Which phenotypes would you expect among the F2 offspring, and how many of each phenotype would you expect? Group of answer choices 192 wild type, 256 vestigial, 64 hairy, and 192 vestigial and hairy All vestigial and hairy. 576 wild type, 192 vestigial, 192 hairy, and 64 vestigial and hairy All wild type 256 wild type; 256 vestigial, 256 hairy, and 256 vestigial and hairyarrow_forwardIn beetles, an X-linked gene determines body size, with normal size (M)completely dominant to miniature body size (m). Body color is determined by an autosomal gene with two alleles, where B is incompletely dominant to b such that BB beetles are black, Bb beetles are brown and bb beetles are yellow. Male beetles are heterogametic (XY). The following cross is performed: brown, miniature sized body female X brown, normal sized body male Based on this information, which of the following statements is FALSE? Select 3 correct answer(s) Question 3 options: A) 1/8 of the female progeny will have yellow miniature bodies. B) All of the male progeny will have miniature bodies. C) 1/4 of the total progeny will be black. D) 1/4 of the male progeny will have yellow miniature bodies. E) All of the female progeny will have miniature bodies.…arrow_forwardConsider the following three autosomal recessive mutations in Drosophila:vestigial wings (v); wild type is long (v+)black body color (b); wildtype is gray (b+)plum eyes (p); wildtype is red (p+)A vestigal, gray, red female (homozygous for all three genes) is crossed with a long wing, black, plum male (homozygous for all three genes). The F1 female progeny are mated with triple homozygous recessive males. Here is the phenotypic data for the F2 progeny:vestigal; gray; red 580long wings; black; plum 592vestigal; black; red 45long; gray; plum 40vestigal; black; plum 89long; gray; red 94vestigal; gray; plum 3long; black; red 5A total of 1448 progeny were counted.Which one of the following values is the approximate distance between the plum eye color and black body color loci?arrow_forward
- You have a Drosophila line that is homozygous for autosomal recessive alleles a, b, and c, linked in that order. You cross females of this line with males homozygous for the corresponding wild-type alleles. You then cross the F1 heterozygous males with their heterozygous sisters. You obtain the following F2 phenotypes (where letters denote recessive phenotypes and pluses denote wild-type phenotypes): 1364 + + +, 365 a b c, 87 a b +, 84 + + c, 47 a + +, 44 + b c, 5 a + c, and 4 + b +.a. What is the recombinant frequency between a and b? Between b and c? (Remember, there is no crossing over in Drosophila males.)b. What is the coefficient of coincidence?arrow_forwardIn Drosophila, the gene for wing type is known to be autosomal with vestigial wings (vg) known to the recessive to normal, long wings (+). You are already familiar with the white eye gene (w) from lecture with the normal color being red (+). Answer the following questions assuming an initial cross (P1) between a pure breeding white eyed, long winged female and a pure breeding red eyed vestigial winged male. a) What are the parental genotypes? b) What phenotypes would occur in the F1 generation and in what proportions? c) What would the phenotypes and phenotypic ratios would occur in F2 generation?arrow_forwardIn Drosophila melanogaster white (w) and miniature (m) wings are controlled by X-linked recessive genes with a recombination fruequency between them of approximately 38%. Show the sexes, phenotypes and proportions of offspring expected from the following mating:a. ++/wm female X wm maleb. +m/w+ female X w+ malec. w+/+m female X ++ maleIf we assume that white eyes and miniature wings are not x-linked but are linkedto the autosomal genes, what phenotypic frequencies would you expect from this cross: ++/wm female X ++/wm male?arrow_forward
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning