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2004-2005 Regents Biology
Genetics
Why do we look the way we do?
2004-2005Regents Biology
Inheritance of chromosomes Egg + sperm zygote
egg
sperm
zygote
fertilizationmitosis &
development
meiosis
2004-2005Regents Biology
Inheritance of genes On the chromosomes passed from
Mom & Dad to offspring are genes may be same information may be different information
eye color(blue or brown?)
eye color(blue or brown?)
2004-2005Regents Biology
Effect of genes _________________________________
_________________________ _________________________ _________________________
2004-2005Regents Biology
Genes affect what you look like
X
Where did the blue eyes go??
BbBb
BB Bb Bb bb
2004-2005Regents Biology
Genes affect what you look like…
X
Why did the blue eyes stay??
BbBb
BB Bb Bb bb
2004-2005Regents Biology
Genes affect what you look like…
X
Where did the blue eyes come from??
BbBb
BB Bb Bb bb
2004-2005Regents Biology
What did we show here? Traits come in “versions”
brown vs. blue eye color __________________
Traits are inherited as separate units brown & blue eye colors are separate &
do not blend brown x blue ≠ brown-blue eyes
Some traits mask others brown eye colors masked blue
2004-2005Regents Biology
Paired chromosomesPaired chromosomes have same kind of information
same types of geneseye color(brown?)
hair color
hair color
eye color
(blue?)
2004-2005Regents Biology
Traits are inherited as separate units
1 from Mom
1 from Dad
For each trait, an organism inherits 2 copies of a gene, 1 from each parent a ____________ organism inherits
1 set of chromosomes from each parent ____________ = 2 sets of chromosomes
__________________
2004-2005Regents Biology
Making gametes This all can be
expressed using letters flower color = P or p
BB = brown eyesbb = blues eyesBb = brown flower
BB
B
B
bb
b
b
Bb
B
bRemember meiosis!
2004-2005Regents Biology
How do we say it?
BB = brown eyesbb = blues eyes
Bb = brown flower
2 of the same________________
2 different________________
BB
B
B
bb
b
b
Bb
B
b
2004-2005Regents Biology
Punnett squares_________________
male / sperm
fem
ale
/ eg
gs
2004-2005Regents Biology
Genetics vs. appearance There can be a difference between
how an organism looks & its geneticsappearance or trait = ___________
brown eyes, blue eyesgenetic makeup = ___________
BB, bb, Bb
2 organisms can have the same appearance but have different genetics: BB vs Bb
2004-2005Regents Biology
Genetics vs. appearance
eye color(brown)
eye color
(brown)
eye color(blue)
eye color
(brown)
vs.
BB
B
BBb
B
b
How were these brown eyes made?How were these brown eyes made?
2005-2006 Regents Biology
Woof! Woof!Any Questions?
