Genetics: From Genes to Genomes, 5th edition
5th Edition
ISBN: 9780073525310
Author: Leland H. Hartwell, Michael L. Goldberg, Janice A. Fischer, Leroy Hood, Charles F. Aquadro
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 4, Problem 21P
The pseudoautosomal regions (PARs) of the X and Y chromosomes enable the sex chromosomes to pair and synapse during meiosis in males. Given the location of the SRY gene near PAR1, can you propose a mechanism for how the mutant X and Y chromosomes in Fig. 4.7 (in which part of the X is on the Y, and part of the Y is on the X) may have arisen during meiosis?
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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 . 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 , or .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 , or .
In an organism with a haploid number of , how many possible combinations of maternal and paternal chromosomes can occur in its gametes?
Select one:
a. 72=49
b. 27=128
c.17=1
d. 214=16 384
Though an individual with abberations such as Robertsonian translocation may be phenotypically normal, they can generate gametes through meiosis that have atypical organizations of chromosomes, resulting in recurrent fetal abnormalities or miscarriages. Why, despite these Robertsonian translocations, are affected cells still able to generate typical gametes through meiosis?
Meiosis is characterized by the pairing of homologouschromosomes during prophase I. In many species, an elaboratestructure called the synaptonemal complex forms betweenhomologues. During this pairing, homologues may exchangechromosomal material at sites called chiasmata. In meiosis I, thehomologues separate from each other, reducing the chromosomenumber to the haploid state (thus the reductive division). It isfollowed by a second division without replication, during whichsister chromatids become separated. The result of meiosis I and IIis four haploid cells.
If sister chromatids separated at the first division, would meiosis still work?
Chapter 4 Solutions
Genetics: From Genes to Genomes, 5th edition
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 - XX males who are sex-reversed because they have a...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 - Does any reason exist that would prevent mitosis...
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 on the next...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 homologous...Ch. 4 - In the moss Polytrichum commune, the haploid...Ch. 4 - Does any reason exist that would prevent meiosis...Ch. 4 - Sister chromatids are held together through...Ch. 4 - The pseudoautosomal regions PARs of the X and Y...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 - 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 at the bottom of the page shows the...Ch. 4 - In 1995, doctors reported a Chinese family in...Ch. 4 - In cats, the dominant 0 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
- 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?arrow_forwardDuring 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 diploid (2n) trihybrid individual with the genotype EeFfGg can make eight genetically different gametes. Loci E/e and F/f are on chromosome 1 and locus G/g is on chromosome 2. Explain how a gamete containing the alleles e, f and g may be produced by meiosis. Refer specifically to meiotic events occurring during Prophase I, Metaphase I, Anaphase I and Anaphase II. (NB: remember to refer to the organism above).arrow_forward
- In fruit flies, chromosomal crossing over does not occur in meiosis in males, whereas crossing over does occur in meiosis in females. In fruit flies that are heterozygous at many genes (i.e. many maternal and paternal versions of the genes differ), at what stage would cells no longer be heterozygous for any gene during the process of meiosis? a)After the second meiotic division in males, and after the first meiotic division in females. b)After the second meiotic division in both males and females. c)After the first meiotic division in both males and females. d)After the first meiotic division in males, and after the second meiotic division in females.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_forwardConsider a cell with 2 pairs of homologous chromosomes where Chromosome 1 with genes VWXYZ is the homolog of Chromosome 2 with genes vwxyz while Chromosome 3 with genes PQRST is the homolog of Chromosome 4 with genes parst. If a reciprocal translocation occurred between Chromosome 1 YZ genes and Chromosome 3 ST genes, give the following gamete types produced after meiosis: (Answer in Arabic numbers only) 1. Gamete/s with non-recombinant chromosomes 2. Gamete/s with 1 recombinant chromosome 3. Gamete/s with 2 recombinant chromosomes 4. Gamete/s with gene duplications 5. Gamete/s with gene deletions 6. Gamete/s with 2 normal chromosome sequences 7. Gamete/s with 1 normal chromosome sequence 8. Gamete/s with balanced translocation 9. Gametes/ with all dominant genes 10. Gamete/s with all recessive genes 11. Gamete/s with 10 different genes 12. Gamete/s with TSXWV genes 13. Gamete/s with vwxyz genes 14. Gamete/s with pqrst genes 15.Gamete/s with PORYZarrow_forward
- An individual heterozygous for a reciprocal translocation possesses the following chromosomes: A B • C D E F G A B • C D V W X R S • T U E F G R S • T U V W X Q. Draw the pairing arrangement of these chromosomes in prophase I of meiosis.arrow_forwardSuppose that meiosis occurs in the transient diploid stageof the cycle of a haploid organism of chromosome number n. What is the probability that an individual haploidcell resulting from the meiotic division will have a complete parental set of centromeres (that is, a set all fromone parent or all from the other parent)?arrow_forwardAn individual is heterozygous for a reciprocal translocation, with the following chromosomes: A • B C D E F A • B C V W X R ST • U D E F R ST • U V W X Q. Draw a picture of these chromosomes pairing in prophase I of meiosis.arrow_forward
- Draw a hypothetical cell’s chromosome configuration undergoing meiosis (show before meiosis, after meiosis I, and then after meiosis II) under each of the following situations: If there is one pair of homologous chromosomes AND there is nondisjunction in meiosis I. If there are two pairs of homologous chromosomes, one labeled ‘A’ and another labeled ‘B’.arrow_forwardThe 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 overarrow_forwardA 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?arrow_forward
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