Choose the statements that best describe the findings based on the graph presented. Mice trisomic at small chromosomes survived longer than mice trisomic at larger chromosomes. There is an inverse relationship between size of the trisomic chromosome and the length of embryonic development. The longer the mice developed, the larger their chromosomes became. There is a positive correlation between size of the trisomic chromosome and the length of embryonic development. Choose the best possible explanation for these results. Being trisomic for larger chromosomes affects the dosage of more genes and is more detrimental, causing development to cease at an earlier stage. Larger chromosomes cause a more rapid onset of chromosomal instability than smaller chromosomes, which leads to earlier death during embryonic development. Being trisomic for smaller chromosomes is less detrimental because a smaller chromosome has less of a chance to develop a lethal mutation. Being trisomic for larger chromosomes causes an imbalance in the number of nucleotide bases normally found in

Choose the statements that best describe the findings based on the graph presented. Mice trisomic at small chromosomes survived longer than mice trisomic at larger chromosomes. There is an inverse relationship between size of the trisomic chromosome and the length of embryonic development. The longer the mice developed, the larger their chromosomes became. There is a positive correlation between size of the trisomic chromosome and the length of embryonic development. Choose the best possible explanation for these results. Being trisomic for larger chromosomes affects the dosage of more genes and is more detrimental, causing development to cease at an earlier stage. Larger chromosomes cause a more rapid onset of chromosomal instability than smaller chromosomes, which leads to earlier death during embryonic development. Being trisomic for smaller chromosomes is less detrimental because a smaller chromosome has less of a chance to develop a lethal mutation. Being trisomic for larger chromosomes causes an imbalance in the number of nucleotide bases normally found in

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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Orangutans are an endangered species in their natural environment (the islands of Borneo and Sumatra), and so a captive-breeding program has been established using orangutans currently held in zoos throughout the world. One component of this program is research into orangutan cytogenetics. This research has shown that all orangutans from Borneo carry one form of chromosome 2, as shown in the accompanying diagram, and all orangutans from Sumatra carry the other form. Before this cytogenetic difference became known, some matings were carried out between animals from different islands, and 14 hybrid progeny are now being raised in captivitya. What term or terms describe the differences between these chromosomes? b. Draw the chromosomes 2, paired in the first meiotic prophase, of such a hybrid orangutan. Be sure to show all the landmarks indicated in the accompanying diagram, and label all parts of your drawing. c. In 30 percent of meioses, there will be a crossover somewhere in the region…
Orangutans are an endangered species in their natural environment (the islands of Borneo and Sumatra), and so a captive-breeding program has been established using orangutans currently held in zoos throughout the world. One component of this program is research into orangutan cytogenetics. This research has shown that all orangutans from Borneo carry one form of chromosome 2, as shown in the accompanying diagram, and all orangutans from Sumatra carry the other form. Before this cytogenetic difference became known, some matings were carried out between animals from different islands, and 14 hybrid progeny are now being raised in captivity.q3.1 q2.2 q2.1 q1.2 q1.1Borneop1.1 p1.2cenq3.1 q2.2 q2.1 p1.1Sumatrap1.2cenq1.1 q1.2a. What term or terms describe the differences between these chromosomes?b. Draw the chromosomes 2, paired in the first meiotic prophase, of such a hybrid orangutan. Be sure to show all the landmarks indicated in the accompanying diagram, and label all parts of your…
In drosophila, a recessive mutation (m-) of a maternal effect gene results in an abnormal phenotype wherein homozygous (m-m-) females produce eggs that cannot support embryonic development. Homozygous (m-m-) males, however, can still produce viable sperm. Using m+ to denote a normal gene, determine the genotypes and phenotypes of the F1s produce by a cross between a heterozygous female and a recessive male. From the offspring, backcross the recessive female with the paternal strain. What are the genotypes and phenotypes of the F2s? Show COMPLETE cross for both cases. If m-m- females produce useless eggs, then how are m-m- produced?
In drosophila, a recessive mutation (m-) of a maternal effect gene results in an abnormal phenotype wherein homozygous (m-m-) females produce eggs that cannot support embryonic development. Homozygous (m-m-) males, however, can still produce viable sperm. Using m+ to denote a normal gene, determine the genotypes and phenotypes of the F1s produce by a cross between a heterozygous female and a recessive male. From the offspring, backcross the recessive female with the paternal strain. 1. What are the genotypes and phenotypes of the F2s? 2. If m-m- females produce useless eggs, then how are m-m- produced?
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?
One of the X chromosomes in a particular Drosophila female had a normal order of genes but carried recessive alleles of the genes for yellow body color (y), vermilion eye color (v), and forked bristles (f), as well as the dominant X-linked Bar eye mutation (B). Her other X chromosome carried the wild-type alleles of all four genes, but the region including y+, v+, and f+ (but not B+) was inverted with respect to the normal order of genes. This female was crossed to a wild- type male in the cross diagrammed her. The cross produced the following male offspring:* table in figure a. Why are there no male offspring with the allele combinations y v f+, v+ v+ f, y v+ f+, or y+ v f (regardless of the allele of the Bar eye gene)?b. What kinds of crossovers produced the y v f b+ and v+ y+ f+ B offspring? Can you determine any genetic distances from these classed of progeny?c. What kinds of crossovers produced the y+ v f+ B+ and y v+ f B offspring?
One of the X chromosomes in a particular Drosophila female had a normal order of genes but carried recessive alleles of the genes for yellow body color (y), vermilion eye color (v), and forked bristles (f), as well as the dominant X-linked Bar eye mutation (B). Her other X chromosome carried the wild-type alleles of all four genes, but the region including y+, v+, and f+ (but not B+) was inverted with respect to the normal order of genes. This female was crossed to a wild-type male in the cross diagrammed her. The cross produced the following male offspring: Y v f B 48 y+ v+ f+ B+ 45 y v f B+ 11 y+ v+ f+ B 8 y v f B 1 y+ v+ f+ B+ 1 a. Why are there no male offspring with the allele combinations y v f+, v+ v+ f, y v+ f+, or y+ v f (regardless of the allele of the Bar eye gene)? b.What kinds of crossovers produced the y v f b+ and v+ y+ f+ B offspring? Can you determine any genetic distances from these classed of progeny? c. What kinds of crossovers produced the…
Consider two hypothetical recessive autosomal genes a and b, where a heterozygote is testcrossed to a double- homozygous mutant. Predict the phenotypic ratios under the following conditions: (a) a and b are located on separate autosomes. (b) a and b are linked on the same autosome but are so far apart that a crossover always occurs between them. (c) a and b are linked on the same autosome but are so close together that a crossover almost never occurs.
In a human genetic study, a family with five phenotypicallynormal children was investigated. Two children were “homozygous”for a Robertsonian translocation between chromosomes19 and 20 (they contained two identical copies of the fusedchromosome). They have only 44 chromosomes but a completegenetic complement. Three of the children were “heterozygous”for the translocation and contained 45 chromosomes,with one translocated chromosome plus a normal copy of bothchromosomes 19 and 20. Two other pregnancies resulted instillbirths. It was later discovered that the parents were firstcousins. Based on this information, determine the chromosomecompositions of the parents. What led to the stillbirths? Whywas the discovery that the parents were first cousins a key pieceof information in understanding the genetics of this family?
The normal sequence of markers on a certain Drosophila chromosome is ABCDE*FGHIJK, where the asterisk represents the centromere. Some flies were isolated with a chromosome aberration that has the following structure: ABCDE*FIJK . This represents a O a) deletion of GH segment O b) inversion of GH segment O c) deletion O d) deletion of centromere
The wild-type (normal) fruit fly, Drosophila melanogaster, has straight wings and long bristles. Mutant strains have been isolated with either curled wings or short bristles. The genes representing these two mutant traits are located on separate chromosomes. Carefully examine the data from the five crosses below. (a) For each mutation, determine whether it is dominant or recessive. In each case, identify which crosses support your answer; and (b) define gene symbols and determine the genotypes of the parents for each cross.
The mutations called bobbed in Drosophila result from variable reductions (deletions) in the number of amplified genes coding for rRNA. Researchers trying to maintain bobbed stocks have often documented their tendency to revert to wild type in successive generations. Propose a mechanism based on meiotic recombination which could account for this reversion phenomenon. Why would wild-type flies become more prevalent in Drosophila cultures?