Coconote
AI notes
AI voice & video notes
Try for free
🌳
Understanding Cystic Fibrosis and Family Trees
Jan 26, 2025
Family Trees and Cystic Fibrosis
Overview of Family Trees
Also known as family pedigrees.
Used to track genetic disorders, like cystic fibrosis, which is recessive.
Genetic Concepts
Cystic Fibrosis
Recessive Inherited Disorder
Requires two recessive alleles (ff) to have the disease.
Dominant healthy allele represented by capital F.
Genotypes
Homozygous Recessive (ff)
: Individual has cystic fibrosis.
Homozygous Dominant (FF)
: Individual does not have cystic fibrosis.
Heterozygous (Ff)
: Individual is a carrier, does not have the disease but can pass the allele.
Family Pedigree Symbols
Circles
: Females.
Squares
: Males.
Unshaded Shape
: Person is unaffected.
Shaded Shape
: Person has the condition.
Half-Shaded Shape
: Person is a carrier.
Always use the provided key to interpret symbols.
Interpreting the Family Tree
Each row represents a new generation.
Top row: Parents
Second row: Children
Bottom row: Grandchildren
Horizontal lines indicate couples.
Unrelated individuals shown due to relationships with family members.
Example Analysis
Family Members
Jenny
: Unaffected female (genotype FF).
Paul
: Carrier male (genotype Ff).
Children
:
Ron & Harry
: Unaffected sons (genotype FF).
Anna & Lucy
: Carrier daughters (genotype Ff).
Sam
: Affected female (genotype ff).
Exam Application
Use the diagram to determine genetic probabilities.
Example: Probability of Lucy and Jack's baby having cystic fibrosis.
Both Lucy and Jack are carriers (genotype Ff).
Use a Punnett square:
1/4 chance (25%) baby is unaffected (FF).
2/4 chance (50%) baby is a carrier (Ff).
1/4 chance (25%) baby has cystic fibrosis (ff).
Conclusion
Understanding family trees and genotypes is crucial for predicting genetic disorders like cystic fibrosis.
Further learning can be pursued through related videos.
📄
Full transcript