6. An X-linked ichthyosis is a recessive form of a family of skin diseases caused by a hereditarydeficiency of the steroid sulfatase (STS) enzyme. A woman heterozygous for this mutation mateswith the phenotypically normal man and produces an XXY son who suffers from the disorder.Which of the answer choices can explain this result? Briefly justify your answer.A) nondisjunction in meiosis I in the fatherB) nondisjunction in meiosis I in the motherC) nondisjunction in meiosis II in the fatherD) nondisjunction in meiosis II in the mother

An X-linked ichthyosis is a recessive form of inherited genetic skin disease that affect males. It…

Answered: 6. An X-linked ichthyosis is a…

BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)

10th Edition

ISBN:9781305967359

Author:STARR

Publisher:STARR

Chapter14: Human Inheritance

Section: Chapter Questions

Problem 2GP: Human females have two X chromosomes XX; males have one X and one Y chromosome XY. a. With respect...

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Human females have two X chromosomes XX; males have one X and one Y chromosome XY. a. With respect to X-linked alleles, how many different types of gametes can a male produce? b. A female homozygous for an X-linked allele can produce how many types of gametes with respect to that allele? c. A female heterozygous for an X-linked allele can produce how many types of gametes with respect to that allele?
3. A man who has polydactyly and normal vision marries a color-blind woman with a normal number of hand and foot digits. The man's father has normal hand and foot digitation, and both the woman's parents have normal hand and foot digitation. A) Polydactyly is autosomal dominant, which means [ Select ] the gene is carried on the X chromosome b. the gene is carried on a non-sex chromosome a. c. the gene is carried on the Y chromosome d. the dominant allele is actually recessive B) Red-green color blindness is X-linked recessive, which means that in females, [ Select ] a. the recessive allele is actually dominant b. the gene is carried on a non-sex chromosome c. the gene must have both recessive alleles to be expressed in the phenotype d. the gene is carried on the Y chromosome C) What proportion of their sons would be color blind and polydactyly? [ Select ] a. half b. none C. one out of four d. all D) What proportion of their daughters would be color blind and polydactyly? [ Select ] а.…
2) Explain how nondisjunction in meiosis is responsible for chromosome abnormalities such as Down syndrome, Klinefelter syndrome, and Turner syndrome.
8. The autosomal (not X-linked) gene for brachydactyly, short fingers, is dominant to normal finger length. Assume that a female with brachydactyly in the heterozygous condition is married to a man with normal fingers. What is the probability that(a) their first child will have brachydactyly?(b) their first two children will have brachydactyly?(c) their first child will be a brachydactylous girl?
Arial 11 BIUA 田回▼ 三=三|三|: 12 II 4. Below is a diploid cell in meiosis. a. Label one set of homologous chromosomes, one set of sister chromatids and one set of heterologous chromosomes. b. How many alleles of the 'A' alleles are present in the cell at Prophase 1? c. How many copies of the 'A' genes are present in each cell at Prophase II? d. How many 'a' alleles are present in Anaphase 1? e. How many 'F' alleles are present in each cell in Metaphase I? f. How many 'f alleles are present in each cell in Metaphase ll? g. How many 'F' genes are present in each gamete? h. How many chromosomes will be present in each gamete? MacBook Air
5. In humans, one type of color-blindness, an inability to distinguish between red and green, is inherited as a sex-linked character on the X chromosome. It is recessive. a) If a color-blind man marries a homozygous normal woman, what chance is there for the children to be color-blind? b) A normal man marries a color-blind woman. Which, if any, of their children are likely to be colorblind? c) Why is it so commonly believed that women cannot be color-blind?
Genetic problems: Use the diagram below to figure out how each monosomy or trisomy can a) Normal X chromosome segregation b) Nondisjunction in meiosis I c) Nondisjunction in meiosis II Diploid cell at start of meiosis First meiotic division Nondisjunction Second meiotic division Nondisjunction 00 00 develop. Benjamim XCuinmi х Х х х Xх хх о о XX O 2. A color-blind man married a normal woman. Their daughter, who was phenotypically normal, married a normal man and the couple produced three children, a normal boy, a color-blind boy, and a color-blind girl. Further examination indicates that this girl has two X chromosomes. Explain the origin of the color- blind girl.
3. A nondisjunction occurs in the sex chromosomes of a male mouse. What ratio of sex chromosome genotypes would you expect among the gametes in the two following scenarios. Make sure to includethe gamete’s sex chromosome genotype in your genotypic ratio. (A) The nondisjunction of the sex chromosomes occurs only in Meiosis I? (B) The nondisjunction of the sex chromosomes occurs only in Meiosis II?
IV. Observation: No Crossing Over Crossing Over Appearance of Gamete Cells Appearance of Gamete Cells V. Analysis: 1. If the two sister chromatids are the same, how are they called? 2. Which specific parts exchanged genetic information during cross over? 3. What is crossing over? 4. When will crossing over occurs? Why? 5. What will happen after crossing over? 6. How do meiosis contributes to genetic variation, while mitosis does not? 7. Why is crossing over important for evolution of species?
1. If an A a Bb C cdd male mates with an A a Bb CC DD female. (a) What is the minimum number of ridge-producing genes possible for a child of this couple? (Show your work. Hint: solve gene by gene) (b) what would be the TRC for this child if it is male? (Show your work: give the formula, place appropriate number in formula and then solve equation). (c) what would be the TRC for this child if it is female? (Show your work: give the formula, place appropriate number in formula and then solve equation).
1. Let's take the example of the gray kangaroo (Macropus fuliginosus) whose ploidy is 8 and the sexual determinism of this species is carried out according to the XY mode. From a male kangaroo: a) Draw the karyotype of this individual, obtained by stopping division at metaphase. Your drawing should include: a. All maternal and paternal chromosomes involved (different colors) b. An example of autosome and heterochromosome c. An example of homologous chromosome, sister chromatid and centromere. d. The total number of chromosomes in a metaphase kangaroo cell. e. A sentence to explain the difference between the terms gene and allele that might apply to this species.
Consider the following pedigree. 하 3 10 (5 3 2 (a) What pattern of transmission is most consistent with this pedigree? (1) autosomal recessive, (2) autosomal dominant, (3) X-linked recessive, (4) X-linked dominant. (b) If individual V-2 marries a normal individual, and if the condition has a pene-trance of 85 percent, what is the probability that their second child will express the trait? (c) On the third line, what does the diamond with a 10 in the middle mean?

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