Download NB 100:Heredity

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Mrs. Aguirre’s Webpage: http://www.quia.com/profiles/caguirre
Heredity Notes 4/9/12
Genes & Alleles
Genes – factors that
control traits Ex:
Earlobe type; pea plant
height
Alleles – different forms
of a gene Ex: Free lobes,
attached lobes; tall plant,
short plant
Truebreeding & Hybrid
True-breeding (or
purebred) organisms with
the same alleles for a trait
Ex: EE or ee; TT or tt
Hybrid organisms with two
different alleles for a trait
Ex: Ee; Tt
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For each genotype, write whether the organism would be purebred
(P) or hybrid (H).
AA
Ee
Ii
Mm
Bb
ff
Jj
nn
Dominant & Recessive
Cc
GG
kk
Oo
Dominant allele – its trait always
shows up in an organism Ex: Free
earlobes; Tall pea plant
Write as CAPITAL LETTERS
Ex: Free earlobes = E
Tall height = T
Recessive allele – its trait is hidden
if the dominant allele is present
Ex: Attached earlobes; Short pea
plant
Write as lowercase letter of
dominant allele
Ex:
Attached earlobes = e
Short height = t
Dd
HH
Ll
Pp
Phenotype & Genotype
Phenotype – form of a trait that an
organism shows
Ex: Free or attached earlobe
Tall or short pea plant
Genotype – the alleles of a gene
that organism has
Examples: EE, ee,
or Ee
TT, tt, or Tt
For each of the genotypes below, determine the phenotype.
Purple flowers are dominant to
white.
Round seeds are dominant to
wrinkled.
PP
RR
Pp
Rr
pp
rr
Yoshi’s green skin color is
recessive (blue is dominant,
although less common)
Skating goofy-footed is dominant
to being regular-footed.
GG
BB
Gg
Bb
gg
bb
For each phenotype, list all the possible genotypes (remember to
use the letter of the dominant trait).
Straight hair is dominant to curly.
Straight (2)
Striped fur is recessive to polkadot fur.
Polka-dot (2)
Curly
Striped
Good-smelling feet are recessive
to stinky feet.
Stinky (2)
Pointed heads are dominant to
round heads.
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