Download Pedigrees

Pedigrees
This is a Pedigree Chart showing
colorblindness in a family
Why are more males than females colorblind?
A Pedigree Chart Is Like A
Family Tree
A Pedigree Chart:
Shows genetic
connections among
individuals
Has Standardized
symbols
May be used to
estimate probability
and patterns of
inheritance over
generations
Basic Symbols of A Pedigree
A Few Extra
Tracing the “Royal Disease”
Hemophilia
Hemophilia is an X-linked recessive disorder characterized by
the inability to properly form blood clots
Became known as the “Royal disease”
because it spread to the royal families of
Europe through the descendents of
Queen Victoria
Became known as “curse of the Coburgs”
Queen Victoria’s Pedigree
What’s the likely
MODE OF TRANSMISSION?
• Autosomal Dominant
• Autosomal Recessive
• Sex-Linked Recessive
Look for the
“male pattern”,
female carriers
What’s the likely
MODE OF TRANSMISSION?
• Autosomal Dominant
• Autosomal Recessive
• Sex-Linked Recessive
In every
generation, no
carriers
What’s the likely
MODE OF TRANSMISSION?
• Autosomal Dominant
• Autosomal Recessive
• Sex-Linked Recessive
Usually skips
generations
But not always!*
Let’s build our own pedigree!
Debbie married David and had three children, Darren, Dawn, and Derek. David,
Darren and Derek discovered they have muscular dystrophy. Derek married Didi
and had two children, Denise and Destiny. Denise also has muscular dystrophy
and married Dirk. They had two children, Dee and Deven. Dee has muscular
dystrophy.
1) Draw the pedigree, showing the relationships between family
members
Let’s build our own pedigree!
Debbie married David and had three children, Darren, Dawn, and Derek. David,
Darren and Derek discovered they have muscular dystrophy. Derek married Didi
and had two children, Denise and Destiny. Denise also has muscular dystrophy
and married Dirk. They had two children, Dee and Deven. Dee has muscular
dystrophy.
2) Identify the phenotype of each family member (affected,
unaffected, carrier, etc.)
Let’s build our own pedigree!
Debbie married David and had three children, Darren, Dawn, and Derek. David,
Darren and Derek discovered they have muscular dystrophy. Derek married Didi
and had two children, Denise and Destiny. Denise also has muscular dystrophy
and married Dirk. They had two children, Dee and Deven. Dee has muscular
dystrophy.
3) Determine the genotype of each family member and the
mode of transmission
Mm
mm
mm
Mm
Mm
mm
mm
mm
Mm
Autosomal Dominant
Mm
mm