Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Chapter 4, Problem 22P
Remarkably, the platypus has 10 sex chromosomes, the largest number found in any mammal. The female platypus has five pairs of different X chromosomes (X1–X5), while the male has X1–X5, and also five different Ys (Y1–Y5). During meiosis in the male, the five Xs always end up together in one gamete, and the five Ys always end up together in another gamete. To achieve this segregation, during prophase of meiosis I the sex chromosomes form a long chain, always in the order X1 Y1 X2 Y2 X3 Y3 X4 Y4 X5 Y5, in which the chromosomes are held together through pseudoautosomal regions (PARs).
| a. | How many different PARs must exist to allow the formation of these chains? (Hint: To answer this question, try drawing the chain of chromosomes.) |
| b. | In terms of pairing ability of the PARs, explain the structural differences between the human and platypus sex chromosomes. |
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A sperm cell from the fruit fly Drosophila melanogaster contains four chromosomes. How many chromosomes would be present in a spermatogonial cell about to enter meiosis? How many chromatids would be present in a spermatogo- nial cell at metaphase I of meiosis? How many would be present at metaphase II?
During meiosis in male mammals, sex chromosomes segregate to produce two types of sperm: X‑bearing sperm and Y‑bearing sperm.
True or false?
The letters below represent genes found on different chromosome pairs. Letters that are similar represent one gene found in a pair of homologous chromosomes. Another letter represents another gene found in another pair of chromosomes. Draw how these different pairs of chromosomes behave during meiosis. Show the complete phases of meiosis for each of the following: (a) Cc (b)BbCC (c)DdEe (d) AAbbCc (e) AaBbCcDd
please do answer all and also show the crossing over
Chapter 4 Solutions
Genetics: From Genes to Genomes
Ch. 4 - Choose the best matching phrase in the right...Ch. 4 - Humans have 46 chromosomes in each somatic cell....Ch. 4 - The figure that follows shows the metaphase...Ch. 4 - Human XX males who are sex-reversed because they...Ch. 4 - Researchers discovered recently that the sole...Ch. 4 - One oak tree cell with 14 chromosomes undergoes...Ch. 4 - Indicate which of the cells numbered iv matches...Ch. 4 - a. What are the four major stages of the cell...Ch. 4 - Answer the questions that follow for each stage of...Ch. 4 - Can you think of anything that would prevent...
Ch. 4 - One oak tree cell with 14 chromosomes undergoes...Ch. 4 - Which types of cell division mitosis, meiosis I,...Ch. 4 - Complete the following statements using as many of...Ch. 4 - The five cells shown in figure a e are all from...Ch. 4 - One of the first microscopic observations of...Ch. 4 - A person is simultaneously heterozygous for two...Ch. 4 - Assuming i that the two chromosomes in every...Ch. 4 - In the moss Polytrichum commune, the haploid...Ch. 4 - Can you think of anything that would prevent...Ch. 4 - Sister chromatids are held together through...Ch. 4 - The pseudoautosomal regions PARs of the X and Y...Ch. 4 - Remarkably, the platypus has 10 sex chromosomes,...Ch. 4 - Somatic cells of chimpanzees contain 48...Ch. 4 - In humans: a. How many sperm develop from 100...Ch. 4 - Women sometimes develop benign tumors called...Ch. 4 - In a certain strain of turkeys, unfertilized eggs...Ch. 4 - Imagine you have two pure-breeding lines of...Ch. 4 - A system of sex determination known as...Ch. 4 - In Drosophila, the autosomal recessive brown eye...Ch. 4 - Barred feather pattern is a Z-linked dominant...Ch. 4 - When Calvin Bridges observed a large number of...Ch. 4 - In a vial of Drosophila, a research student...Ch. 4 - In 1919, Calvin Bridges began studying an X-linked...Ch. 4 - In Drosophila, a cross was made between a...Ch. 4 - As we learned in this chapter, the white mutation...Ch. 4 - The following is a pedigree of a family in which a...Ch. 4 - Each of the four pedigrees that follow represents...Ch. 4 - The pedigree that follows indicates the occurrence...Ch. 4 - Duchenne muscular dystrophy DMD is caused by a...Ch. 4 - The X-linked gene responsible for DMD encodes a...Ch. 4 - Males have hemophilia when they are hemizygous for...Ch. 4 - In the Fast Forward Box Visualizing X Chromosome...Ch. 4 - Consider the following pedigrees from human...Ch. 4 - Several different antigens can be detected in...Ch. 4 - The ancestry of a white female tiger bred in a...Ch. 4 - The pedigree that follows shows the inheritance of...Ch. 4 - In 1995, doctors reported a Chinese family in...Ch. 4 - In cats, the dominant O allele of the X-linked...Ch. 4 - In marsupials like the opposum or kangaroo, X...Ch. 4 - The pedigree diagram below shows a family in which...
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- Figure 13.6 Which of the following statements about nondisjunction is true? Nondisjunction only results in gametes with n+1 or n-1 chromosomes. Nondisjunction occurring during meiosis II results in 50 percent normal gametes. Nondisjunction during meiosis I results in 50 percent normal gametes. Nondisjunction always results in four different kinds of gametes.arrow_forwardHuman 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_forwardA diploid organism produces four gametes from one parent cell through the process of meiosis. Two gametes are found to have 7 chromosomes and two gametes are found to have 5 chromosomes. A) Is this the expected number of chromosomes that would be found in each gamete following a normal cycle of meiosis? If yes, explain why. If no, explain why not and describe how the gamete situation described above occurred. B) Determine the number of homologous chromosome pairs that the original parent cell contained, before meiosis began. Explain how you determined this value.arrow_forward
- During metaphase I of meiosis, tetrads align along the metaphase plate independently of each other. Therefore, there is a random “shuffle” of maternal and paternal chromosomes in the resulting gametes.The following diagram demonstrates how this works in a diploid cell with four chromosomes (2n=4) . Because there are two pairs of chromosomes and each pair can align in one of two ways during metaphase I, the number of possible variations in the gametes produced is 22 or 4.For an organism that is , there are three pairs of chromosomes, so the number of possible variations in the gametes produced due to independent assortment in metaphase I is 23 or 8. In an organism with a haploid number of 7, how many possible combinations of maternal and paternal chromosomes can occur in its gametes? a. 72=49 b. 27=128 c.17=1 d. 214=16 384arrow_forwardA certain species of animal has 18 chromosomes in its diploid cells (2n=18). Describe what the metaphase chromosome arrangement would look like for this species in each of the following stages: mitosis, meiosis I, and meiosis IIarrow_forwardIf nondisjunction occurs in humans for one pair of homologous chromosomes during meiosis I. The other pairs segregate normally. a) Will any normal gametes result? b) How many chromosomes will each human gametehave? If nondisjunction occurs in humans for sister chromatids during meiosis II. The other pairs segregate normally. a) Will any normal gametes result? b) How many chromosomes will each human gamete have?arrow_forward
- The letters below represent genes found on different chromosome pairs. Letters that are similar represent one gene found in a pair of homologous chromosomes. Another letter represents another gene found in another pair of chromosomes. Draw how these different pairs of chromosomes behave during meiosis. Show the complete phases of meiosis for each of the following: (a) Cc (b)BbCC (c)DdEe (d) AAbbCc (e) AaBbCcDdarrow_forwardMatch the following: A duplicated chromosome is made of 2.A maternal and paternal chromosome present together, each with two sister chromatids 3.Semi-condensed DNA made up of coiled nucleosomes. 4.Super-coiled DNA strands. 5.Contains only one copy of each chromosome. 6.Name of an error during meiosis resulting in fewer chromosomes than normal in a zygote or individual (2n-1) 7.General term for an error resulting in the incorrect number of chromosomes in a gamete after meiosis 8.A specific version of a gene, such as blue eye colour 9.A region on a chromosome that codes for a protein 10.Region where chromosomes are attached 11.None of the above (should be selected more than once) with monosomy trisomy aneuploidy centromere gene sister chromatids diploid Haploid tetrad telomere Chromosomes Chromatin allelearrow_forwardA diploid cell in a Canadian beaver will have 20 pairs of homologous chromosomes. Which of the following would best describe the DNA in a haploid gamete for this beaver? (Read carefully!) 20 unique chromosomes 40 unique chromosomes 20 pairs of homologous chromosomes 10 unique chromosomes 10 pairs of homologous chromosomesarrow_forward
- During oogenesis in an animal species with a haploid number of 6, one dyad undergoes nondisjunction during meiosis II. Following the second meiotic division, this dyad ends up intact in the ovum. How many chromosomes are present in (a) the mature ovum and (b) the second polar body? (c) Following fertilization by a normal sperm, what chromosome condition is created?arrow_forwardMeiosis is also known as reduction cell division because it reduces the ploidy level from diploid (2n) to haploid (n). Why do we need to reduce our ploidy level in certain cells?arrow_forwardAssume that you were examining a first polar body and noted that it had one copy (dyad) of each chromosome except chromosome 21. Chromosome 21 was completely absent. What would you expect to be the chromosome 21 complement (only with respect to chromosome 21) in the secondary oocyte? What consequences are likely in the resulting zygote if the secondary oocyte was fertilized?arrow_forward
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