The direction of shell coiling in the snail Lymnaea peregra (discussed in the introduction to this chapter) results from genetic maternal effect. An autosomal allele for a right-handed, or dextral, shell (s+) is dominant over the allele for a left-handed, or sinistral, shell (s). A pet snail called Martha is sinistral and reproduces only as a female (the snails are hermaphroditic). Indicate which of the following statements are true and which are false. Explain your reasoning in each case. Q. Martha’s genotype must be ss.

The direction of shell coiling in the snail Lymnaea peregra (discussed in the introduction to this chapter) results from genetic maternal effect. An autosomal allele for a right-handed, or dextral, shell (s+) is dominant over the allele for a left-handed, or sinistral, shell (s). A pet snail called Martha is sinistral and reproduces only as a female (the snails are hermaphroditic). Indicate which of the following statements are true and which are false. Explain your reasoning in each case. Q. Martha’s genotype must be ss.

Name: The direction of shell coiling in the snail Lymnaea peregra (discussed
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Description: The direction of shell coiling in the snail Lymnaea peregra (discussed in the introduction to this chapter) results from genetic maternal effect. An autosomal allele for a right-handed, or dextral, shell (s+) is dominant over the allele for a left-ha

Human Biology (MindTap Course List)

11th Edition

ISBN:9781305112100

Author:Cecie Starr, Beverly McMillan

Publisher:Cecie Starr, Beverly McMillan

Chapter20: Chromosomes And Human Genetics

Section: Chapter Questions

Problem 2CT: Human sex chromosomes are XX for females and XY for males. a. With respect to an X-linked gene, how...

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The direction of shell coiling in the snail Lymnaea peregra (discussed in the introduction to this chapter) results from genetic maternal effect. An autosomal allele for a right-handed, or dextral, shell (s+) is dominant over the allele for a left-handed, or sinistral, shell (s). A pet snail called Martha is sinistral and reproduces only as a female (the snails are hermaphroditic). Indicate which of the following statements are true and which are false. Explain your reasoning in each case. Q. At least some of the offspring produced by Martha must be sinistral
The direction of shell coiling in the snail Lymnaea peregra (discussed in the introduction to this chapter) results from genetic maternal effect. An autosomal allele for a right-handed, or dextral, shell (s+) is dominant over the allele for a left-handed, or sinistral, shell (s). A pet snail called Martha is sinistral and reproduces only as a female (the snails are hermaphroditic). Indicate which of the following statements are true and which are false. Explain your reasoning in each case. Q. Martha’s genotype cannot be s+ s+.
The direction of shell coiling in the snail Lymnaea peregra (discussed in the introduction to this chapter) results from genetic maternal effect. An autosomal allele for a right-handed, or dextral, shell (s+) is dominant over the allele for a left-handed, or sinistral, shell (s). A pet snail called Martha is sinistral and reproduces only as a female (the snails are hermaphroditic). Indicate which of the following statements are true and which are false. Explain your reasoning in each case. Q. All of Martha’s brothers must be sinistral
The direction of shell coiling in the snail Lymnaea peregra (discussed in the introduction to this chapter) results from genetic maternal effect. An autosomal allele for a right-handed, or dextral, shell (s+) is dominant over the allele for a left-handed, or sinistral, shell (s). A pet snail called Martha is sinistral and reproduces only as a female (the snails are hermaphroditic). Indicate which of the following statements are true and which are false. Explain your reasoning in each case. a. Martha’s genotype must be ss. b. Martha’s genotype cannot be s+ s+. c. All the offspring produced by Martha must be sinistral. d. At least some of the offspring produced by Martha must be sinistral. e. Martha’s mother must have been sinistral. f. All of Martha’s brothers must be sinistral
Researchers discovered recently that the sole functionof the SRY protein is to activate an autosomal genecalled Sox9 in the presumptive gonad (before it has“decided” to become a testis or an ovary).a. What would be the sex of an XY individual homozygous for nonfunctional mutant alleles of Sox9?Explain.b. Given your answer to part (a), why is SRY, ratherthan Sox9, considered the male determining factor?(Hint: What do you think would happen if you didan experiment like the one in the Fast Forward BoxTransgenic Mice Prove That SRY Is the MalenessFactor, except that you used a Sox9 transgeneinstead of SRY?)
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?
As it turned out, one of the tallest Potsdam Guards had an unquenchable attraction to short women. During his tenure as guard, he had numerous clandestine affairs. In each case, children resulted. Subsequently, some of the childrenwho had no way of knowing that they were relatedmarried and had children of their own. Assume that two pairs of genes determine height. The genotype of the 7-foot-tall Potsdam Guard was A9A9B9B9, and the genotype of all of his 5-foot clandestine lovers was AABB. An A9 or B9 allele in the offspring each adds 6 inches to the base height of 5 feet conferred by the AABB genotype. a. What were the genotypes and phenotypes of all the F1 children? b. Diagram the cross between the F1 offspring, and give all possible genotypes and phenotypes of the F2 progeny
For this problem, use the information given in problem 15. A young woman with blood type O gave birth to a baby with blood type O. In a court case, she claims that a certain young man is the father of her child. The man has type A blood. Could he be the father? Can it be proven on this evidence alone that he is the father? ^Need answers to that one, including genotype, phenotype gametes and punnett square. This is question 15 as a little background dont need this solved . In humans, there are three alleles for blood type: A, B, and O. The allele for blood type A and the allele for blood type B show incomplete dominance. A person with both alleles has blood type AB. Both A and B dominate type O. A person with alleles for blood types A and O marries someone with alleles for blood types B and O. List the types of blood their offspring could have and the probability for each blood type in the offspring
Duchenne muscular dystrophy, which is inherited in an X-linked recessive pattern, nearly always occurs in males. Explain why.
Hemophilia is another example of an X-linked disease caused when a recessive allele (Xh) is expressed. If a normal male reproduces with a heterozygous normal female, what are the expected genotypes and phenotypes? Will any of their daughters develop hemophilia?
Hemophilia is another example of a X-linked disease caused when a recessive allele (Xh) is expressed. If a normal male reproduces with a heterozygous normal female, what are the expected genotypes and phenotypes? Will any of their daughters develop hemophilia? As in the previous question, you must also give the gender of the child in your genotype and phenotype descriptions here.
This pedigree exhibits a maternal effect. What is the genotype of each individual?