Download Introduction to Inheritance - California Foundation for

The Wonderful World of Diversity:
Introduction to Human
Inheritance
Who’s in the family?
Talk the Talk:
• Heredity
• Trait
• Gene
• DNA
• Chromosome
• Allele
• Genotype
• Phenotype
• Heterozygous
• Homozygous
Dominant and Recessive Traits
• For each of our traits, we inherit one allele
from Mom and one from Dad.
• One allele usually expresses itself (we can see
it) and the other remains hidden. The
expressed allele is dominant and the allele we
can’t see is recessive.
• Example: If curly tail is dominant to straight
tail, a puppy who received a curly tail allele
from its mother and a straight tail allele from
its father will have a curly tail.
Human Traits
• No Widows Peak (W). Widow’s peak (w). My phenotype =
• Dimples (D). No Dimples (d). My phenotype =
• Freckles (F). No Freckles (f). My phenotype =
• Hand Cross Right Thumb Top (R). Left Thumb Top ( r ).
My phenotype =
• Tongue Rolling (T). No Tongue Rolling (t). My phenotype =
• Free earlobe (E). Attached Earlobe (e). My phenotype =
Human Traits
Trait
No Widow’s
Peak
Widow’s Peak
Dimples
No Dimples
Freckles
No Freckles
Right Thumb
Cross
Left Thumb
Tongue Roller
Non Tongue
Free Earlobe
Attached Earlobe
Class
Ratio Students
Percent of
Tally
with Trait / Total
Students with
Students
Trait
Make a graph of the class data for
those expressing the recessive
phenotype.
Make a graph of the class data for
those expressing the dominant
phenotype.
Conduct a Survey
• Work with a partner
• Survey at least 20 people for traits that were
studied in class
• People must agree to take part in your survey
Trait
Widow’s Peak
No Widow’s Peak
Dimples
No Dimples
Freckles
No Freckles
Right Thumb Cross
Left Thumb Cross
Tongue Roller
Non Tongue Roller
Free Earlobe
Attached Earlobe
Total Number of People Surveyed
Tally
Explain it:
Use key vocabulary to write a
paragraph that explains how traits
are inherited and why this results
in a wide range of phenotypes.