Download traits - Canton Local Schools

Dominant and
Recessive Traits
What are traits?
• Physical Traits
– Can be seen by others
– Eye color, hair color, height, left handed
• Acquired Traits
– Learned skills
– Playing a sport, riding a bike, playing a musical
instrument
• Behavioral Traits
– Instinctual actions
– Nest building and migration
Review Terms Used in
Modern Genetics
• Genotype
– The particular alleles (genes) an individual carries
– They are inherited from your biological parents
– Genes control your traits
• Phenotype
– An individual’s observable traits
• What people can SEE when they look at you
Review Terms Used in
Modern Genetics
• An individual with non-identical alleles of a
gene is heterozygous for that gene
– Examples: Bb, Tt, Aa
• An individual with identical alleles of a gene is
homozygous for that gene
– Examples: BB or bb, TT or tt
Terms Used in Modern Genetics
• An allele is dominant if its effect masks the
effect of a recessive allele paired with it
– Capital letters (A) signify dominant alleles;
lowercase letters (a) signify recessive alleles
– Homozygous dominant (AA)
– Homozygous recessive (aa)
– Heterozygous (Aa)
What traits do you have?
• We will go through the most common traits
that people have
• On your sheet, record if you have the
mentioned trait or not
• You may have to ask your neighbor for help 
Detached (EE, Ee) or attached (ee)
Earlobes
Can Tongue Roll (TT, Tt) or Can’t
(tt)
Dimples (DD, Dd) No Dimples (dd)
Right (RR, Rr) or Left (rr) handed?
Freckles (FF, Ff) No Freckles (ff)
Curly (HH, Hh) or Straight (hh)
Cleft Chin (CC, Cc) or No Cleft (cc)
Allergies (AA, Aa) or No Allergies (aa)
Hand Clasp Right over Left?
Normal (BB, Bb) Color Blindness (bb)
Can you see the
number inside
the circle?
If you cannot,
you may be
colorblind
Widow’s Peak (WW, Ww)
or Straight (ww)
Data
• We will now record our class data and graph
our results
• Does our data support which genes are
dominant and which genes are recessive?
• What about the whole 7th grade?