Concept explainers
Data analysis Two different genes have mutant alleles that cause this spotting
To determine: The function of other gene product in spotting phenotype, if one gene encodes a signaling molecule.
Introduction: A mutation can be defined as a sudden change that occurs in the DNA sequence, during DNA replication. It can also be caused by exposure to specific chemicals or radiation. Mutation contributes to genetic variability.
Explanation of Solution
Neural crest cell under the surface of ectoderm differentiates into pigment cells of the skin. Survival and migration of these cellsare affected by a mutation in genes leads to white spotting in the skin. Two different genes have a mutant allele that causes the spotting phenotype in humans and mice. One gene act as a signaling molecule then the other is likely to be a receptor for the molecule.
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Chapter 52 Solutions
BIOLOGY
- Enhanced Spatial Learning in Mice With an Autism Mutation Autism is a neurobiological disorder with symptoms that include impaired social interactions and stereotyped patterns of behavior. Around 10 percent of autistic people have an extraordinary skill or talent such as greatly enhanced memory. Mutations in neuroligin 3, an adhesion protein that connects brain cells to one another, have been associated with autism. One mutation changes amino acid 451 from arginine to cysteine. In 2007, Katsuhiko Tabuchi and his colleagues genetically modified mice to carry the same arginine-to-cysteine substitution in their neuroligin 3. Mice with the mutation had impaired social behavior. To test spatial learning ability, the mice were placed in a water maze: a deep pool of warm water in which a platform is submerged a few millimeters below the surface. The platform is not visible to swimming mice. Mice do not particularly enjoy swimming, so they locate a hidden platform as fast as they can. When tested again, they can remember its location by checking visual cues around the edge of the pool. How quickly they remember the platforms location is a measure of spatial learning ability (FIGURE 15.18). FIGURE 15.18 spatial learning ability in mica mutation in neuroligin 3 (R451C), compared with unmodified (wild-type) mica. 2. Did the modified or the unmodified mice learn the location of the platform faster in the first test?arrow_forwardEffect of Paternal Grandmothers Food Supply on Infant Mortality Researchers are investigating long- reaching epigenetic effects of starvation, in part because historical data on periods of famine are widely available. Before the industrial revolution, a failed harvest in one autumn typically led to severe food shortages the following winter. A retrospective study has correlated female infant mortality at certain ages with the abundance of food during the paternal grandmothers childhood. FIGURE 10.12 shows some of the results of this study. FIGURE 10.12 Graph showing the relative risk of early death of a female child, correlated with the age at which her paternal grandmother experienced a winter with a food supply that was scarce (blue) or abundant (red) during childhood. The dotted line represents no difference in risk of morality. A value above the line means an increases risk; one below the line indicates a reduced risk. 3. There was no correlation between early death of a male child and eating habits of his paternal grandmother, hut there was a strong correlation with the eating habits of his paternal grandfather. What does this tell you about the probable location of epigenetic changes that gave rise to these data?arrow_forwardEffect of Paternal Grandmothers Food Supply on Infant Mortality Researchers are investigating long- reaching epigenetic effects of starvation, in part because historical data on periods of famine are widely available. Before the industrial revolution, a failed harvest in one autumn typically led to severe food shortages the following winter. A retrospective study has correlated female infant mortality at certain ages with the abundance of food during the paternal grandmothers childhood. FIGURE 10.12 shows some of the results of this study. FIGURE 10.12 Graph showing the relative risk of early death of a female child, correlated with the age at which her paternal grandmother experienced a winter with a food supply that was scarce (blue) or abundant (red) during childhood. The dotted line represents no difference in risk of morality. A value above the line means an increases risk; one below the line indicates a reduced risk. 1. Compare the mortality of girls whose paternal grandmothers ate well at age 2 with that of those who experienced famine at the same age. Which girl was more likely to die early? How much more likely was she to die?arrow_forward
- Enhanced Spatial Learning Ability in Mice Engineered to Carry an Autism Mutation Autism is a neurobiological disorder with symptoms that include impaired social interactions and repetitive, stereotyped patterns of behavior. Around 10 percent of autistic people also have an extraordinary skill or talent such as greatly enhanced memory. Mutations in the gene for neuroligin 3, an adhesion protein that connects brain cells, have been associated with autism. One of these mutations is called R451C because the altered gene encodes a protein with an amino acid substitution: a cysteine (C) instead of an arginine (R) in position 451. In 2007, Katsuhiko Tabuchi and his colleagues introduced the R451C mutation into the neuroligin 3 gene of mice. The researchers discovered that the genetically modified mice had impaired social behavior and superior spatial learning ability. Spatial learning in mice is tested with a water maze, which consists of a small platform submerged a bit below the surface or a pool of water so it is invisible to a swimming mouse. Mice do not particularly enjoy swimming, so they try to locate the hidden platform as quickly as they can. When tested again later, they remember the platforms location by checking visual cues around the edge or the pool. How quickly they remember is a measure of their spatial learning ability. FIGURE 15.14 shows some or Tabuchis result. FIGURE 15.14 Spatial learning ability in mice. Mice with a mutation in neuroligin 3 (R451C) were tested for learning performance: as compared with unmodified (wild-type) mice. Did the modified or the unmodified mice learn the location of the platform faster in the first test?arrow_forwardThe photos below show flowers from two Arabidopsis plants. One plant is wild-type unmutated; the other carries a mutation in one of its ABC floral identity genes. This mutation causes sepals and petals to form instead of stamens and carpels. Refer to Figure 10.7 to decide which gene A, B, or C has been inactivated by the mutation.arrow_forwardTay-Sachs disease is an autosomal recessive disease. Affected individuals do not often survive to reproductive age. Why has Tay-Sachs persisted in humans?arrow_forward
- Please answer fast The two mutations we observed were ebony body and vestigial wings. Could the type of mutation affect the outcome of the cross (i.e. skew the number of each kind of fly)? Why or why not? Hint: think about how a particular mutation might affect the life of the fly.arrow_forwardGo to the NCBI’s website at https://ncbi.nlm.nih.gov On the database dropdown menu, select “Gene” and search for “RB1.” The first entry should be on the Homo sapiens version; click the gene name. Use the information to answer the following: What is the chromosomal location of RB1? Scroll down to the “Expression” data. List 2-3 examples of normal tissues that typically express the RB1 gene. Would you say that RB1 expression is very specific or general within tissues? Scroll down to the “NCBI Reference Sequences (RefSeq)” section. Click on the “GenBank” link under NG_009009.1 RefSeqGene. This will take you to the genomic sequence of RB1. How many nucleotides long is the full-length RB1 gene? Return to the RefSeq section in the Gene Database for RB1 (back click once from where you were for part c). Click on the link under “mRNA and Protein(s)” listed as NM_000321.3. This will take you to the mature mRNA sequence data: How many bases long is the full-length RB1 mRNA transcript? Scroll…arrow_forwardfill in the blank: a. lincRNA plays a role in regulating ___ making genes but they themselves are encoded in the genome that is considered _____ DNA. b. The most well known example of RNA regulating the expression of DNA is the production of the ___ that coats one copy of the X chromosome in a female forming the ____.arrow_forward
- Although each cell in your body contains the same set of genes, the genes that are “turned on” differ depending on the type of cell. What signals different genes to be “turned on” or transcribed in different cells? What types of behaviours or environmental circumstances can lead to changes in an individual’s epigenome? Explain. 3. Explain how changes in your epigenome can alter the DNA of your future children before they are even born. 4.) Explain TWO implications of these findings for society. (Hint: think big! Implications for how disease is transmitted, intergenerational trauma, the cycle of poverty, etc.)arrow_forwardEnhanced Spatial Learning Ability in Mice Engineered to Carry an Autism Mutation Autism is a neurobiological disorder with symptoms that include impaired social interactions and repetitive, stereotyped patterns of behavior. Around 10 percent of autistic people also have an extraordinary skill or talent such as greatly enhanced memory. Mutations in the gene for neuroligin 3, an adhesion protein that connects brain cells, have been associated with autism. One of these mutations is called R451C because the altered gene encodes a protein with an amino acid substitution: a cysteine (C) instead of an arginine (R) in position 451. In 2007, Katsuhiko Tabuchi and his colleagues introduced the R451C mutation into the neuroligin 3 gene of mice. The researchers discovered that the genetically modified mice had impaired social behavior and superior spatial learning ability. Spatial learning in mice is tested with a water maze, which consists of a small platform submerged a bit below the surface or a pool of water so it is invisible to a swimming mouse. Mice do not particularly enjoy swimming, so they try to locate the hidden platform as quickly as they can. When tested again later, they remember the platforms location by checking visual cues around the edge or the pool. How quickly they remember is a measure of their spatial learning ability. FIGURE 15.14 shows some or Tabuchis result. FIGURE 15.14 Spatial learning ability in mice. Mice with a mutation in neuroligin 3(R451C) were tested for learning performance: as compared with unmodified (wild-type) mice. In the first test, how many days did it take unmodified mice to learn to find the location of a hidden platform in 10 seconds?arrow_forwardEnhanced Spatial Learning in Mice With an Autism Mutation Autism is a neurobiological disorder with symptoms that include impaired social interactions and stereotyped patterns of behavior. Around 10 percent of autistic people have an extraordinary skill or talent such as greatly enhanced memory. Mutations in neuroligin 3, an adhesion protein that connects brain cells to one another, have been associated with autism. One mutation changes amino acid 451 from arginine to cysteine. In 2007, Katsuhiko Tabuchi and his colleagues genetically modified mice to carry the same arginine-to-cysteine substitution in their neuroligin 3. Mice with the mutation had impaired social behavior. To test spatial learning ability, the mice were placed in a water maze: a deep pool of warm water in which a platform is submerged a few millimeters below the surface. The platform is not visible to swimming mice. Mice do not particularly enjoy swimming, so they locate a hidden platform as fast as they can. When tested again, they can remember its location by checking visual cues around the edge of the pool. How quickly they remember the platforms location is a measure of spatial learning ability (FIGURE 15.18). FIGURE 15.18 spatial learning ability in mica mutation in neuroligin 3 (R451C), compared with unmodified (wild-type) mica. 1. In the first, how many days did it take unmodified mice to learn to find the location of the hidden platform within 10 seconds?arrow_forward
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