Symbols
What shape represents a male?
Square
What is a pedigree?
A family tree showing inheritance of a trait
Where is the oldest child placed?
Left side
Can a recessive disorder skip generations?
Yes
What genotype must an affected recessive individual have?
gg
What shape represents a female?
Circle
What is a genotype
The allele combination for a trait
How are siblings connected?
By a horizontal sibship line
If two healthy parents have an affected child, the disorder is probably…?
Recessive
What genotype is a carrier?
Gg
What does a shaded symbol mean?
The person has the trait/disorder
What is a phenotype
The observable characteristic/trait
How are children connected to parents?
Vertical line downward
Dominant disorders usually appear in how many generations?
Every generation
What does G_ mean?
One dominant allele known, second allele unknown
What line connects parents in a pedigree?
Horizontal line
What is a carrier?
Someone who has one recessive allele but does not show the disorder
What direction do generations move?
Top to bottom
Gg × gg → chance of affected child?
50%
Can a healthy person be Gg?
Yes
What does a half-shaded symbol usually represent?
Carrier
What does homozygous mean?
Having two identical alleles
Can two affected recessive parents have a healthy child?
No
GG × gg → chance of affected child?
0%
If both parents are Gg, what is the chance of an affected child?
25%