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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 platform’s 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?
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Chapter 15 Solutions
Biology: The Unity and Diversity of Life (MindTap Course List)
- 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_forwardTwo types of mutations discussed in this chapter are (1) nucleotide changes and (2) unstable genome regions that undergo dynamic changes. Describe each type of mutation.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. Did the modified or the unmodified mice learn the location of the platform faster in the first test?arrow_forward
- The following is a portion of a protein: met-trp-tyr-arg-gly-pro-thr-Various mutant forms of this protein have been recovered. Using the normal and mutant sequences, determine the DNA and mRNA sequences that code for this portion of the protein, and explain each of the mutations. a. met-trp- b. met-cys-ile-val-val-leu-gln- c. met-trp-tyr-arg-ser-pro-thr- d. met-trp-tyr-arg-gly-ala-val-ile-ser-pro-thr-arrow_forwardBloom Syndrome Bloom syndrome is a rare genetic disorder. It is characterized by a short stature and a long narrow face with prominent nose and ears. There is also an increased sensitivity to light. People who have the disorder often develop rashes on their face, forearms, and hands when they have been exposed to the sun. In addition, these people often suffer from chronic obstructive pulmonary disorder (COPD) and have a higher chance of developing cancer. The cause of this genetic disorder is a mutation in the BLM gene located on chromosome 15. The immediate effect of this mutation is that there is a defect in the functioning of the DNA helicase enzyme. The location of this gene on the chromosome is indicated above (yellow arrow). What is the effect of this mutation on DNA replication? What stage of the cell cycle would be most affected?arrow_forwardHomozygosity for extremely rare mutations in a humangene called SCN9A cause complete insensitivity topain (congenital pain insensitivity or CPA) and a totallack of the sense of smell (anosmia). The SCN9A geneencodes a sodium channel protein required for transmission of electrical signals from particular nerves inthe body to the brain. The failure to feel pain is a dangerous condition as people cannot sense injuries.The SCN9A gene has 26 exons and encodes a1977-amino acid polypeptide. Consanguineous matings in three different families have resulted in individuals with CPA/anosmia. In Family 1, a G-to-Atransition in exon 15 results in a truncated protein that is898 amino acids long; in Family 2, deletion of a singlebase results in a 766-amino acid polypeptide; and inFamily 3, a C-to-G transversion in exon 10 yields a458-amino acid protein.a. Hypothesize as to how each of the three SCN9Amutations affects gene structure: Why are truncatedproteins made in each case? b. How would you…arrow_forward
- short answer please! thank you!arrow_forwardPlease arrangearrow_forwardTHE MOLECULAR GENETICS OF CYSTIC FIBROSIS and of The following is the base sequence of DNA that codes for amino acids 506-510 of the protein that regulates the chlorine channels in the cell membrane. This protein contains a total of 1476 amino acids so this is a small part of the entire gene. DNA Template Strand: 3'TAGTAGAAACCACAA5' 1. What is the minimum number of DNA nucleotides in this whole gene? 2. What is the sequence of bases on the strand of DNA that is complementary to the template strand? 3. What mRNA will be formed from the template strand of DNA? 4. What amino acids will this mRNA code for? 5. If the 6th, 7th and 8th bases in the template strand of the DNA are removed, rewrite the new template strand below. 6. When the template strand of the DNA is changed, this is referred to as a mutation. What kind of mutation is this? 65arrow_forward
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