Mendelian Inheritance Flashcards
What are the mechanisms of inheritance?
Pedigrees
In a pedigree what does the circle represent?
Female
In a pedigree what does the square represent?
Male
In a pedigree what does the diamond represent?
Unknown sex
In a pedigree what does a filled in shape represent?
Affected individual
In a pedigree what does a 1/2 filled in shape represent?
Heterozygous individual
In a pedigree what does the small circle represent?
Spontaneous abortion
In a pedigree what does a shape with a line through it represent?
Deceased
In a pedigree what does a line between a circle and a square represent?
Mating
In a pedigree what does 2 lines between a circle and a square represent?
Consanguineous mating
In a pedigree what does a point with 2 lines coming from it represent?
Dizygotic twins
In a pedigree what does a line going to a point with 2 lines coming from it represent?
Monozygotic twins
In a pedigree what does a filled in shape represent?
Affected individual
In a pedigree what do roman numerals designate?
Generation number
In a pedigree what do arabic numerals designate?
Individuals within generations
In a pedigree what do arabic numerals designate?
Individuals within generations
In human genetics which sex is drawn first?
Male
In human genetics which sex is drawn first?
Male
What is autosomal dominant/
Only 1 copy of a gene is needed to influence expression
What is phenotype?
Physical presentation
What is genotype?
Specific allele or DNA variation
What is autosomal dominant?
Only 1 copy of a gene is needed to influence expression
What is genotype?
Specific allele or DNA variation
What is a punnet square?
Shows combinations of alleles from the fertilization of an egg with a sperm in a square
What are the rules of autosomal dominant?
- Affected offspring have at least 1 affected parent
- Unaffected individuals don’t transmit the trait
- Both males & females can transmit the trait to both males & females
- The trait is expected in every generation at roughly 50%
What is autosomal recessive?
2 copies of a gene is needed to influence expression
What is autosomal recessive?
2 copies of a gene is needed to influence expression
What are the rules of autosomal dominant?
- Most affected individuals have normal parents
- Average 1:4 siblings affected
- Both males & females may be affected
- Affected individuals who mate with normal individuals tend to have normal offspring
- If trait is rare, it is more likely to occur in consanguineous mating
What are the rules of autosomal dominant?
- Most affected individuals have normal parents
- Average 1:4 siblings affected
- Both males & females may be affected
- Affected individuals who mate with normal individuals tend to have normal offspring
- If trait is rare, it is more likely to occur in consanguineous mating
What are the rules of autosomal dominant?
- Most affected individuals have normal parents
- Average 1:4 siblings affected
- Both males & females may be affected
- Affected individuals who mate with normal individuals tend to have normal offspring
- If trait is rare, it is more likely to occur in consanguineous mating
What are the rules of X-linked recessive
- Unaffected males don’t transmit the trait
- Female carriers transmit affected allele to 50% of sons & daughters
- All daughters of affected males are heterozygous carriers
What are the rules of X-linked recessive?
- Unaffected males don’t transmit the trait
- Female carriers transmit affected allele to 50% of sons & daughters
- All daughters of affected males are heterozygous carriers
What are the rules of X-linked dominant?
- No carriers
- Both males & females affected
- Females transmit the trait to 50% of males & females
- Males transmit the trait to no sons & 100% daughters
What are the different pedigree types of Mendelian inheritance?
- Autosomal dominant
- Autosomal recessive
- X-linked recessive
- X-linked dominant
What are the different pedigree types of Mendelian inheritance?
- Autosomal dominant
- Autosomal recessive
- X-linked recessive
- X-linked dominant
What is penetrance?
Frequency with which a gene manifests itself in a population
In a pedigree what does a lightly shaded shape represent?
An individual with the genotype but not the phenotype
In a pedigree what does a lightly shaded shape represent?
An individual with the genotype but not the phenotype
What is expressivity?
Term used to describe the range of phenotypes associated with a specific genotype
