Concept explainers
a.
To determine: The trait as recessive or dominant according to the offspring produced.
Introduction. The genetic material is all the living organism is the DNA (deoxyribonucleic acid). All the eukaryotes as well the prokaryotes have defined set of DNA sequence, which is inherited from one generation to another and codes for all the characters of the organism.
b.
To determine: The presence of trait as autosomal or sex linked.
Introduction. The DNA (deoxyribose
c.
To determine: The genotypes of parent and progeny.
Introduction. The process of
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Introduction to Genetic Analysis
- This pedigree traces the inheritance of a rare disease in humans. a. Based on this pedigree, is the allele for this disease dominant or recessive? Explain. b. What genotypes are possible for the individuals labeled 1, 2, and 3?arrow_forwardFragile X syndrome is an X-linked recessive Achondroplasia is an autosomal dominant trait characterized by a shortened stature. An XX individual is a carrier for Fragile X disorder and is unaffected by achondroplasia. An XY individual is not affected by Fragile X disorder and has achondroplasia. a. What is the XX individual’s genotype b. What is the XY individual’s genotype? c. If the two individuals where to have children, what are the possible genotypes and phenotypes of their children? Use a Punnett square. d. What is the probability of them having a child with Fragile X and achondroplasia?arrow_forwardIN DROSOPHILA, AN X-LINKED RECESSIVE MUTATION, Xm CAUSES MINIATURE WINGS. LIST THE F₂ PHENOTYPIC RATIOS IF: A MINIATURE-WINGED FEMALE IS CROSSED WITH A NORMAL MALE AND A MINIATURE-WINGED MALE IS ● ● CROSSED WITH A NORMAL FEMALE. WHAT WOULD THE PHENOTYPIC RATIO FROM (A) BE IF THE MINIATURE- WINGED GENE WERE AUTOSOMAL? ASSUME IN ALL CASES THAT THE P1 INDIVIDUALS ARE TRUE-BREEDING.arrow_forward
- Determine what is the most likely mode of inheritance of this disease (whether it is inherited as the result of an X-linked dominant or X-linked recessive trait). Use "A" for the allele associated with the dominant phenotype, and lowercase "a"" for the allele associated with the recessive phenotype. Write the most probable genotype for each individual based on the mode of inheritance you have determined. Show how all the partners are crossed and the expected offspring produced (You may use Punnett Square). OT I OT do IIarrow_forwardIn the fruit fly, Drosophila melanogaster, eye color is affected by an X-linked gene with two alleles, w for white eyes and w+ for the wild-type red eyes. White eyes is a recessive trait. Females from a true-breeding strain with wild type eyes are crossed with males that have white eyes. a. What will be the phenotypes in the F1 generation? b. What will be the phenotypes in the F2 generation and in what portions are they expected?arrow_forwardAnhidrotic ectodermal dysplasia is an X-linked recessive disorder in humans characterized by small teeth, no sweat glands, and sparse body hair. This trait is usually seen in men, but women who are heterozygous carriers of the trait often have irregular patches of skin with few or no sweat glands (see the illustration below). a. Explain why women who are heterozygous carriers of a recessive gene for anhidrotic ectodermal dysplasia have irregular patches of skin lacking sweat glands. b. Why does the distribution of the patches of skin lacking sweat glands differ among the females depicted in the illustration, even between the identical twins?arrow_forward
- In fruit flies, ken– is the mutant allele of a gene and ken+ is the wild-type allele. vg- is the mutant allele of the vestigial gene and vg+ is the wild-type allele. Both phenotypes show an autosomal recessive mode of inheritance. Which of the following fly genotypes should result in a wild-type fly? (Select all that apply.)arrow_forwardraccoons may have wide, medium-sized, or narrow bands around their tails. They may also havethe habit of washing all, or some of their food, or do not wash their food at all. a) assign genotypes to the phenotypes mentioned (see attached table) b. What mode of inheritance would most likely be exhibited by these traits if crosses were made? c. If two raccoons with medium-sized tail bands and have the habit of washing some of theirfoods will be crossed, what is the probability of having F1 raccoons with: c.1 wide tail bands that won’t wash any of their food? c.2 the same genotype as the parent raccoons? d. If a raccoon with a wide tail band that washes only some of its food is crossed with a raccoonwith a narrow tail band that doesn’t wash any food, what percentage of their offspring wouldbe medium-tailed and washes all its food? Show COMPLETE cross.arrow_forwardIn the snail Cepaea nemoralis, an autosomal allele causing a banded shell (BB) is recessive to the allele for an unbanded shell (BO). Genes at a different locus determine the background color of the shell; here, yellow (CY) is recessive to brown (CBw). A banded, yellow snail is crossed with a homozygous brown, unbanded snail. The F1 are then crossed with banded, yellow snails (a testcross). a. What will the results of the testcross be if the loci that control banding and color are linked with no crossing over? b. What will the results of the testcross be if the loci assort independently? c. What will the results of the testcross be if the loci are linked and 20 m.u. apart?arrow_forward
- In humans, the genes for coloblindedness and hemophilia re both located on the X chromosome with no corresponding gene in the Y. These are both recessive alleles. a. If a man and a woman, both with normal vision, marry and have a colorblind son, draw the Punnet square that illustrates this. b. If the man dies and the woman remarries to a colorblind man, draw a Punnet Square showing the type of children could be expected from hre second marriage. How many/what percentages of each could ne expectedarrow_forwardIn the snail Cepaea nemoralis, an autosomal allele causing a banded shell (BB) is recessive to the allele for an unbanded shell (BO). Genes at a different locus determine the background color of the shell; here, yellow (CY) is recessive to brown (CBw). A banded, yellow snail is crossed with a homozygous brown, unbanded snail. The F1 are then crossed with banded, yellow snails (a testcross). Q.What will the results of the testcross be if the loci are linked and 20 m.u. apart?arrow_forwardIn the snail Cepaea nemoralis, an autosomal allele causing a banded shell (BB) is recessive to the allele for an unbanded shell (BO). Genes at a different locus determine the background color of the shell; here, yellow (CY) is recessive to brown (CBw). A banded, yellow snail is crossed with a homozygous brown, unbanded snail. The F1 are then crossed with banded, yellow snails (a testcross). Q.What will the results of the testcross be if the loci assort independently?arrow_forward
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