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Human Genome Variation and Mutation Mechanisms
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Human Genome Variation and Mutation Mechanisms
Chapter 3 Study Human Genome Variation and Mutation Mechanisms
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1
Question
What is the main focus of Chapter 3 in this text?
Answer
Human genome variation and its mechanisms of change (mutation) and effects.
2
Question
What term describes DNA sequence differences that usually have no discernible effect on fitness?
Answer
Neutral alleles.
3
Question
What theory explains that most genetic differences do not affect evolutionary fitness?
Answer
Neutral theory of molecular evolution.
4
Question
What is the term for genetic differences that influence phenotype and may be heritable?
Answer
Genetic variations affecting phenotype (genotype-phenotype differences).
5
Question
What are the two basic inheritance patterns discussed for disease-causing mutations in a diploid organism?
Answer
Dominant and recessive.
6
Question
What term describes a mutation that causes a phenotype when only one copy is mutated?
Answer
Dominant mutation.
7
Question
What term describes a mutation that requires mutations in both gene copies to manifest disease?
Answer
Recessive mutation.
8
Question
In dominant disorders, what does full penetrance mean?
Answer
All individuals with the mutant allele show the disorder.
9
Question
What does reduced penetrance mean in some dominant allele cases?
Answer
Not all carriers express the phenotype.
10
Question
What does the term haplotype refer to in the context of allele combinations on a chromosome?
Answer
The set of alleles at multiple loci that are transmitted together.
11
Question
What is the component called that functions as a chloride channel and is defective in CF?
Answer
Cystic fibrosis transmembrane conductance regulator (CFTR).
12
Question
What are carriers in the context of recessive diseases?
Answer
Individuals with one mutant and one normal allele.
13
Question
What genotype indicates two identical mutant alleles for a gene?
Answer
Homozygous mutant.
14
Question
What genotype indicates two different alleles for a gene?
Answer
Heterozygous.
15
Question
Which genetic concept explains why some people with a dominant mutation may not show the disease?
Answer
Incomplete (reduced) penetrance.
16
Question
Which pages discuss mitochondrial DNA variation?
Answer
Section 3.3 (Sequence variation in mitochondrial DNA).
17
Question
What type of variation involves repeats of DNA sequences in tandem?
Answer
Tandemly repeated DNA sequence variation.
18
Question
What section addresses transposable elements in the genome?
Answer
Section 3.5 (Transposable element insertions).
19
Question
What scale of variation encompasses millions of base pairs and can be seen cytologically?
Answer
Structural variation.
20
Question
What projects mapped patterns of genome variation across continents?
Answer
HapMap and 1000 Genomes projects.
21
Question
What is the major purpose of studying genome variation in humans?
Answer
Understand how variation arises, spreads, and affects phenotype and disease.
22
Question
How many genome copies do ~7 billion people carry?
Answer
About 14 billion genome copies.
23
Question
What term describes differences in phenotype caused by genotype differences?
Answer
Genotype-phenotype differences.
24
Question
What term denotes a DNA sequence change that is common in the population but typically not disease-causing?
Answer
Polymorphism.
25
Question
What environmental or medical traits are affected by genetic variation beyond visible traits?
Answer
Blood group, HLA type, drug response, disease susceptibility.
26
Question
What is the genetic basis of phenotypes like color vision deficiencies and bitter taste?
Answer
Genetic variation linked to sensory traits.
27
Question
What does the term ‘wild-type’ refer to in population genetics?
Answer
The typical allele in a reference population.
28
Question
Why is it difficult to conceive a single normal genome?
Answer
Many alleles are neutral or have unknown effects.
29
Question
What is meant by copy-number variation (CNV)?
Answer
Differences in the number of copies of DNA segments among individuals.
30
Question
What section discusses the effects of age on mutation rate?
Answer
Section 3.7 (The effects of age and sex on mutation rate).