Genetics/Hereditary Flashcards
(25 cards)
What does the Law of Dominance state?
In a cross of pure parents, only one form of a trait appears in the next generation.
What is the outcome of crossing pure parents according to the Law of Dominance?
All offspring will be heterozygous and express only the dominant trait.
What does the Law of Segregation describe?
During the formation of gametes, two alleles responsible for a trait separate from each other.
What does the Law of Independent Assortment state?
Alleles for different traits separate independently during the making of gametes.
How are alleles for a trait recombined?
They are recombined at fertilization to produce the genotype for traits of offspring.
What determines blood type?
Blood type is determined by multiple alleles.
How many different alleles can a person carry for a particular gene?
A person can carry at most 2 different alleles.
What are blood types classified as?
Positive or negative based on the existence of the Rh factor/RhD antigen.
What is the significance of the RhD antigen in blood type?
If the RhD antigen is present, the blood type is positive; if absent, it is negative.
Why is blood type O-negative considered a universal donor?
It doesn’t have A or B antigens or the Rh factor, so it can be given without harmful reactions.
What is a universal recipient blood type?
AB+ is a universal recipient because it does not produce antibodies against AB or Rh antigens.
What are the genotypes for blood type A?
I^A I^A or I^A i.
What are the genotypes for blood type B?
I^B I^B or I^B i.
What is the genotype for blood type AB?
I^A I^B.
What is the genotype for blood type O?
ii.
What characterizes autosomal dominant inheritance?
Most generations affected, inherited from either parent, males and females affected at the same rate.
Can autosomal dominant traits be inherited from unaffected parents?
No, they cannot be inherited from unaffected parents.
What defines autosomal recessive inheritance?
Can be inherited from unaffected parents, males and females affected at the same rate.
What is a characteristic of X-linked recessive inheritance?
Males are affected more than females and can inherit from unaffected mothers.
Why are X-linked traits more likely to be presented in males?
Males have only one X chromosome, so a recessive gene on it will show the trait.
What is required for females to show an X-linked recessive trait?
Females need two copies of the recessive gene to show the trait.
Name three autosomal recessive genetic disorders.
- Cystic fibrosis
- Tay-Sachs disease
- Sickle cell anemia
Name one autosomal dominant genetic disorder.
Huntington’s disease.
