Concept explainers
Introduction: The genes present on the chromosomes have alleles. They define the phenotypic and genotypic traits of the person. The types of alleles include dominant and recessive condition, which are depicted by a capital letter and a small letter for, example B for a dominant allele and b for a recessive allele of a gene. The combination of both the genes after recombination defines the
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Campbell Essential Biology with Physiology (5th Edition)
- Which of the following is true of recessive sex-linked genes? A. A female showing the trait will pass it on to all of her sons who will all show the trait. B. A female showing the trait will pass it on to all of her daughters who will all show the trait. C. A male showing the trait will pass it on to all of his sons who will all show the trait. D. A male showing the trait will pass it on to all of his daughters who will all show the trait.arrow_forwardWhen a disease is due to polygenic inheritance, the following is probably true: A. Many factors, both genetic and environmental, contribute to the disease traits. B. It is caused by one gene with a large number of alleles. C. It affects a large number of people. D. It has many different symptomsarrow_forwardA type of baldness is sex –limited such that the allele that causes it is dominant in men and recessive in women. Thus baldness is much more common in men than women even though the locus is on an autosome. How is the pattern of inheritance in this example different from X-linked inheritance of a recessive allele? Group of answer choices A. the trait can be passed from fathers to sons B. the trait can be passed from fathers to daughters C. the trait can be passed from mothers to sons D. the trait can be passed from mothers to daughtersarrow_forward
- Alleles that show incomplete dominance will represent: Choose oneAnswer: A . heterozygotes that have a phenotype intermediate between the dominant and recessive alleles. B. homozygotes that have a genotype like the recessive allele C. homozygotes that have a phenotype intermediate between the dominant and recessive alleles. D. heterozygotes that have a genotype like the dominant allelearrow_forwardTay–Sachs disease is caused by recessive alleles on anautosome. In which case(s) could two parents with anormal phenotype have a child with Tay–Sachs?a. Both parents are homozygous for a Tay–Sachs allele.b. Both parents are heterozygous for a Tay–Sachsallele.c. One parent is homozygous for a Tay–Sachs allele,and the other is heterozygous.arrow_forwardSome heterozygotes express a phenotype that is intermediate between the dominant and recessive phenotype. For example, in 4 o’clock flowers the gene for red pigmentation is dominant and the gene for white pigmentation is recessive. However, heterozygotes are pink. The dominant allele does not completely mask expression of the recessive allele: it is incompletely dominant. a. By observing flower color in 4 o’clock flowers, is it possible to unambiguously determine the genotype? YES/NO. Explain your answer. b. Is the same true for flower color in snow peas? YES/NO Why or why not?arrow_forward
- Which of the following is true of genomic imprinting? a. The sex of the parent that transmits an allele affects the expression of the allele in the offspring. b. The sex of the offspring affects the expression of an allele inherited from one of the parents. c. The sex of the parent affects how an allele is transmitted to the offspring. d. The sex of the offspring affects which allele is inherited from the parent.arrow_forwardWhich of the following is NOT true of Y-linked traits? Select one: a. They are always expressed. b. They are extremely uncommon in females. c. They are passed from father to son. d. They carry both dominant and recessive alleles of a trait.arrow_forwardWhat must be true about the genotypes of parents who have a child who has an: a. dominant trait? b. recessive trait?arrow_forward
- A is a dominant gene for normal pigment, and a is its recessive allele for albinism (and pink eyes). B is a dominant gene for brown eyes, and b is its recessive allele (blue). What is the mother's genotype if two brown-eyed parents have fraternal twins, one with blue eyes and one with pink eyes (albino)? a. AaBb b. AaBB c. aaBb d. aabb e. AABBarrow_forwarda. Determine if the pedigree below can be for a trait that is X-linked traits. Write the genotype of each individual next to the symbol. b. Is it possible that this pedigree is for an X-linked recessive trait? c. What can you conclude about the children if both parents are affected with an X-linked recessive trait?arrow_forwardIn humans, a dimple in the chin is a dominant characteristic controlled by a single gene. A man who does not have a chin dimple has children with a woman with a chin dimple whose mother lacked the dimple. What proportion of their children would be expected to have a chin dimple? A man with a chin dimple and a woman who lacks the dimple produce a child who lacks a dimple. What is the man’s genotype? A man with a chin dimple and a non-dimpled woman produce eight children, all having the chin dimple. Can you be certain of the man’s genotype? Why or why not? What genotype is more likely, and why?arrow_forward
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