• Dominance: widow's peak.

• Recessive: attached earlobe, Rh factor.

• Incomplete dominance: hair texture.

• Codominance and multiple alleles: ABO blood group.

• Polygene inheritance: hair color.

• X-linked inheritance: Mother usually passes recessive allele to son; both parents pass recessive alleles to daughter.

Review the traits in Table 19.1, complete the data sheet for your phenotype.

Trait	Phenotype		Genotype
Dimples	Dimples	No dimples
Earlobes	Free	Attached
Tongue	Roller	Non-roller
Widow's	Peak	No-peak
Rh factor	Positive	Negative
Freckles	Yes	No
Hitchhiker's	Thumb	No-Thumb
Hair Form	Curly	Wavy	Straight
Blood	Type O	Type A	Type B	Type AB
Hair Color	Dark Brown/Black	Brown	Red	Sandy/Titan	Blond
Thiourea Taste	Taster	Non-Taster
PTC Taste	Taster	Non-Taster
Sodium Benzoate Taste	Taster	Non-Taster
Gender	Male	Female
Color Vision	Normal	Colorblind
Interlocking Fingers	Left Over Right	Right Over Left

• Answer the questions using the figures.