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Intro to Genetics. CATALYST. Brown eyes Fast Runner Blue eyes Normal Vision Near Sightedness Dark hair Hardworking Straight Hair Widow ’ s peak Dimples Attached earlobes Freckles Pierced Ears Allergies Tongue-rolling. Which traits do you think come from your DNA? Why ? - PowerPoint PPT Presentation
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Intro to Genetics
CATALYST1. Which traits
do you think come from your DNA? Why?
2. Which traits do you think come from your environment? Why?
Brown eyesFast RunnerBlue eyes
Normal VisionNear Sightedness
Dark hairHardworkingStraight HairWidow’s peak
DimplesAttached earlobes
Freckles Pierced Ears
AllergiesTongue-rolling
GREGOR MENDEL
3
http://science.discovery.com/videos/100-greatest-discoveries-shorts-genetics.html
What do you
know?
What is a gene?
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GREGOR MENDEL
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You inherit2copies of every gene, one
from eachPARENT
gamete
Each copy is called anALLELE
In most cases, each gene has a
DOMINANT &RECESSIVE
allele possibility
GREGOR MENDEL
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These alleles (GENES)
determine what proteins get
made/expressed (TRAITS)
Gene alleles are inherited
INDEPENDENTLY of other
genes.
Example: Just because you
inherited Brown hair, does not mean you will
have brown eyes
VOCABULARYGENOTYPE
VS. PHENOTYPE
Genotype: the genes that make up your body; the “type of genes” you have
Example: AA, Aa, aa, RR, Rr, rr
Phenotype: what we look like; our physical appearanceExample: Brown hair, blue eyes, tall height
VOCABULARY
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Brown hair.
VOCABULARY
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Bb.
VOCABULARY
10
Small hands.
VOCABULARY
11
ss
DOMINANT VS. RECESSIVEGenes are what you INHERIT from each PARENT. Every gene will have two forms or alleles, DOMINANT or RECESSIVE.
DOMINANT: the allele that shows up, or can be seen is dominant. STRONGWritten as: CAPITAL LETTERS Example: R, S, T, Q, M, N, D
RECESSIVE: the allele that is seen only when both alleles are recessive. WEAK.Written as: LOWER-CASE LETTERS Example: r, s, t, q, m, n, d•If the trait for “big nose” is the dominant trait, use “B” to represent the dominant allele.
•If the trait “small nose” is the recessive trait, use “b” to represent the recessive allele.
Don’t change the LETTER, just the capitalization!!!!
•Only 1 dominant allele must be inherited for the dominant trait to be expressed (show up)Example: BB or Bb
•2 recessive alleles must be inherited for a recessive trait to be expressed (show up)Example: bb
NN = __________________ Nn= __________________ nn= __________________
DOMINANT DOMINANT RECESSIVE
DOMINANT VS. RECESSIVE
VOCABULARY
14
GENOTYPEVS.
PHENOTYPE
VOCABULARY
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Dominant or Recessive?
T
VOCABULARY
16
Dominant or Recessive?
k
VOCABULARY
17
Dominant or Recessive?
L
HOMOZYGOUS VS. HETEROZYGOUS
HOMOZYGOUS: both letters (alleles) are the SAME• HOMO- : same• Example: BB, RR, mm, LL, hh, TT, dd
HETEROZYGOUS: each letter is DIFFERENT or MIXED• HETERO- : different or mixed• Example: Hh, Bb, Rr, Tt, Ll, Kk Ss, Gg
There are 3 combinations of alleles (genotypes):
1. Homozygous Dominant (DD) Phenotype = Dominant2. Heterozygous (Dd)Phenotype = Dominant3. Homozygous Recessive (dd) Phenotype = Recessive
Additional Terms:
Homozygous= True/Pure Breeding
Heterozygous = Hybrid
VOCABULARY
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HeterozygousHomozygous
DominantHomozygous
Recessive
VOCABULARY
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HH
VOCABULARY
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Dd
VOCABULARY
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dd
VOCABULARY
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Oo
GREEN
GREEN
YELLOW
HOMOZYGOUS DOMINANTHOMOZYGOUS RECESSIVEHETEROZYGOUS
TT
Tt
tt SHORT
TALL
TALL HOMOZYGOUS DOMINANT
HOMOZYGOUS RECESSIVE
HETEROZYGOUST
t
___ :Wrinkled
___: Smooth
W
w
WW
Ww
ww
WRINKLED
WRINKLED
SMOOTH
HOMOZYGOUS DOMINANT
HETEROZYGOUS
HOMOZYGOUS RECESSIVE
HD
HE
HE
HE
HR
HE
HE
HE
HR
HE
HR
HR
PURPLEPURPLEWHITE
BROWNBROWNBLUE
ROUNDROUND
WRINKLED
LONGTAILLONGTAIL
BOBTAIL
SS
Ss
ss
PP
Pp
pp
Small EyesNormal TeethFreckles
Gentoype = Tt (Heterozygous)Phenotype = Normal Teeth
Gentoype = ff (Homozygous Recessive)Phenotype = Freckles