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Questions and Answers
What is an allele?
What is an allele?
How many different genotypes can be formed from two alleles?
How many different genotypes can be formed from two alleles?
Which of the following options describes a Single Nucleotide Polymorphism (SNP)?
Which of the following options describes a Single Nucleotide Polymorphism (SNP)?
What is the normal phenotype for a genotype represented as 'Cc' in relation to cystic fibrosis?
What is the normal phenotype for a genotype represented as 'Cc' in relation to cystic fibrosis?
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Which amino acid is deleted in patients with cystic fibrosis?
Which amino acid is deleted in patients with cystic fibrosis?
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On which chromosome is the cystic fibrosis gene located?
On which chromosome is the cystic fibrosis gene located?
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What is the primary function of the protein encoded by the cystic fibrosis gene?
What is the primary function of the protein encoded by the cystic fibrosis gene?
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Which statement about alleles is correct?
Which statement about alleles is correct?
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What is a feature of X-chromosome inactivation relevant to genetic disorders in females?
What is a feature of X-chromosome inactivation relevant to genetic disorders in females?
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How does inbreeding affect the likelihood of offspring being homozygous for recessive deleterious alleles?
How does inbreeding affect the likelihood of offspring being homozygous for recessive deleterious alleles?
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What factor is associated with Charles II of Spain's genetic disorders?
What factor is associated with Charles II of Spain's genetic disorders?
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What does calculating the inbreeding coefficient (f) help determine?
What does calculating the inbreeding coefficient (f) help determine?
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What is the primary outcome of consanguineous marriages in genetic terms?
What is the primary outcome of consanguineous marriages in genetic terms?
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Why might offspring of first cousins have a higher chance of inheriting a rare recessive allele?
Why might offspring of first cousins have a higher chance of inheriting a rare recessive allele?
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Which statement correctly describes the mutation inheritance represented in the pedigree?
Which statement correctly describes the mutation inheritance represented in the pedigree?
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Which of the following is NOT an implication of X-chromosome inactivation for females with genetic disorders?
Which of the following is NOT an implication of X-chromosome inactivation for females with genetic disorders?
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What is the primary alteration that leads to the disease discussed?
What is the primary alteration that leads to the disease discussed?
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Which amino acid is lost due to the ΔF508 mutation?
Which amino acid is lost due to the ΔF508 mutation?
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What inheritance pattern is exhibited by the mutations leading to this disease?
What inheritance pattern is exhibited by the mutations leading to this disease?
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What is the probability of having an affected offspring if both parents are carriers of the mutation?
What is the probability of having an affected offspring if both parents are carriers of the mutation?
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What does the disruption of the CFTR protein's amino acid sequence lead to?
What does the disruption of the CFTR protein's amino acid sequence lead to?
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In cases of autosomal recessive disorders, how many copies of the mutation must be inherited to express the phenotype?
In cases of autosomal recessive disorders, how many copies of the mutation must be inherited to express the phenotype?
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How might autosomal dominant disorders manifest differently than recessive ones?
How might autosomal dominant disorders manifest differently than recessive ones?
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What does the genetic notation 'C c' indicate in the context of inheritance?
What does the genetic notation 'C c' indicate in the context of inheritance?
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What is the probability that an individual inherits two identical 'A' alleles from its great-grandparents?
What is the probability that an individual inherits two identical 'A' alleles from its great-grandparents?
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Which of the following statements is true regarding the inbreeding coefficient (f) for allele 'B'?
Which of the following statements is true regarding the inbreeding coefficient (f) for allele 'B'?
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How is the inbreeding coefficient (f) mathematically represented for alleles inherited from both parents?
How is the inbreeding coefficient (f) mathematically represented for alleles inherited from both parents?
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What is the significance of the probability $1/26$ in the context of this content?
What is the significance of the probability $1/26$ in the context of this content?
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If the chance that sibs share the 'A' allele is ¼, what does this imply regarding allele inheritance?
If the chance that sibs share the 'A' allele is ¼, what does this imply regarding allele inheritance?
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For allele 'D', what is the calculated probability of inheriting two alleles from great-grandparents?
For allele 'D', what is the calculated probability of inheriting two alleles from great-grandparents?
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What denotes the end of inbreeding calculations represented in this content?
What denotes the end of inbreeding calculations represented in this content?
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Which allele has the same probability of inheritance as allele 'C'?
Which allele has the same probability of inheritance as allele 'C'?
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What is the probability that an individual is homozygous for alleles if inherited alleles are identical?
What is the probability that an individual is homozygous for alleles if inherited alleles are identical?
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What is the significance of inbreeding coefficients in the context of genetics?
What is the significance of inbreeding coefficients in the context of genetics?
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Study Notes
BY450 Fundamentals of Genetics & Evolution
- Course name: BY450 Fundamentals of Genetics & Evolution
- Topic: Alleles, Genotypes, Phenotypes
- Instructor: Andy Overall
Alleles
- An allele is a variant of a gene/locus.
- Genes/loci can vary in a number of ways. This variation can be as small as a single nucleotide difference (Single Nucleotide Polymorphism) or as large as an entire gene duplication.
- Alleles are depicted using letters, for example, allele A and allele B for gene X.
- A gene may have multiple alleles.
Genotypes and Phenotypes
- The combination of alleles an individual has is called their genotype, for example, AA, AB, or BB for gene X.
- The observable characteristics of an organism are called its phenotype.
- Two alleles can be responsible for phenotypic differences between organisms.
Cystic Fibrosis
- Cystic fibrosis is a genetic disorder caused by a mutation in the CFTR gene on chromosome 7.
- The most common mutation is the deletion of three nucleotides (CTT) in the CFTR gene. This deletion causes the loss of the amino acid phenylalanine at position 508 in the CFTR protein.
Autosomal Recessive Inheritance
- Mutations that result in the loss of a functional gene product (e.g., insertions, deletions, premature stop codons, and frame shift mutations) often show recessive inheritance.
- Two copies of the mutation are required to display the mutation phenotype (individual needs two mutant copies ).
Pedigrees
- Pedigrees are diagrams that show the inheritance of traits through generations.
- Analyzing pedigrees can help determine if a trait is autosomal dominant, autosomal recessive, X-linked recessive, or X-linked dominant.
Autosomal Dominant Inheritance
- Disorders result from mutations which often manifest in either gene products with novel functions or genes expressed in an unregulated fashion.
- Males and females affected in equal proportions.
- Individuals affected in multiple generations.
Sex-Linked Inheritance
- Mutations on the X-chromosome show X-linked inheritance.
- In X-linked recessive inheritance, males are more likely to be affected than females. A male only needs one copy of the affected X chromosome to have the disorder.
- X-chromosome inactivation can influence the expression of X-linked disorders in females.
Inbreeding Coefficient (f)
- The risk of offspring inheriting deleterious recessive mutations is greater in inbred populations, i.e. mating between close relatives.
- Close relatives are more likely to share the same alleles, resulting in homozygosity for recessive traits.
- The inbreeding coefficient (f) calculates the probability that two alleles in an individual are identical by descent.
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Description
Test your knowledge on alleles, genotypes, and phenotypes in genetics. Explore the variations in genes and how they contribute to observable characteristics in organisms. This quiz also covers genetic disorders like cystic fibrosis and their underlying causes.
