Pedigrees Flashcards
What do the circle and square symbols represent in a pedigree?
Circle– female
Square– male
A shaded shape indicated that a _________ is present.
–trait
A half shaded shape indicates a _____________.
– carrier
True or False–
Horizontal lines connecting male and females represents siblings.
False, represents marriage
Vertical lines are used to link ____________ to ____________.
Parents to offspring
What are the two steps in interpreting a pedigree?
- Determine if the pedigree chart shows an autosomal or sex-linked disease
- Determine whether the disorder is dominant or recessive
How do you determine if the disease in the pedigree is autosomal or sex-linked disease?
If most of the males in the pedigree are affected the disorder is sex-linked
If it is a ________ ratio between males and females the disorder is ____________.
50/50 ; autosomal
If the disorder is ________, one of the parents must have the disorder.
Dominant
If the disorder is recessive, neither parent has to have the disorder because they can be _____________.
Heterozygous
A blending of traits–
Incomplete dominance
True or False
Two alternative forms of a gene that are both dominant resulting in a blending of traits is called incomplete dominance.
True
In incomplete dominance, they are ALWAYS __________ dominant.
Homozygous
Two forms of a gene contribute to the phenotype–
Codominance
Traits for which there are more than two forms of a particular gene–
Multiple alleles