Download Genetics - VA Biology SOL

CATALYST
 Catalyst:
Complete a dihybrid
cross for a Heterozygous Tall
person and a Homozygous Short
Person. T = Tall, t = Short
 Mr.
Gibney will start this on board
promptly when bell rings
 CURRENT EVENT BY FRIDAY!!!!
HOMEWORK REVIEW
CURRENT EVENTS (I will give
you till Wednesday)
-HELP US See Science in
everyday life
“Very nice résumé. Leave a sample
of your DNA with my secretary.”
Gibney Bucks Review!!!
 How do mitosis and meiosis differ?
 How are people either male or female?
 What is DNA?
 What is replication?
 What is transcription?
 What is translation?
 When is Reading day this week?
STUDY
ROCK THIS
CLASS
YOU CAN
BRING
YOUR
GRADE UP
IF YOU TRY!
Think for a second about
the most crazy thing you
have ever seen…
Imagine in the future…
when something like THIS
could be possible…
The future is now…
WELCOME TO
GENETICS!!!
Follow Along
• In Book Ch 10
• Fill in guided notes as
we go along and if
you miss something…
check out the book!
•WHY THIS IS IMPORTANT!!!!!!
GENETICS
the study of how
traits are passed from
one generation to the
next
TRAIT
a characteristic
Examples:
Plant size, seed color, pod shape
TRAITS YOU
MIGHT
HAVE…
 Can
you curl
your tongue?
 Can you
wiggle your
ears?
 Can you raise
just one
eyebrow?
 USA:
82% Yes
 USA:
27% Yes
 USA:
64% Yes
GENES
Each feature of the pea plants is controlled by a
gene. It may have a gene that controls its color,
another for size and another for shape.
GENE
the factors that
control traits
(found in the DNA)
Above you see chromosomes. The circled
area is a gene on chromosome #22. The
absence of this gene causes velo-cardiofacial syndrome (VCFS) which may
cause ADD and mental illness
ALLELES
Each gene comes in different forms called alleles,
so the gene that controls flower color may come
in two alleles: purple and white.
ALLELES
different forms
of a gene
PURPLE MAN EATER PLANT
EXAMPLE
 Traits:
6ft tall, purple, eats people
 Genes that control these traits are on
Chromosome 17
 Each of the three genes has different
alleles: Can be 6ft tall or 3 ft tall, purple or
orange, eat people or vegetarian
GREGOR MENDEL





The “father” of genetics
Lived from 1822-1884
Austrian Monk
Published his work in
1866, but no one took him
seriously until 1900.
Studied Pea Plants!
MENDEL’S
EXPERIMENTS
Mendel experimented with 7
different characteristics
Mendel Got Lucky for 2 Big Reasons
1.
2.
First, he had a lot of time…he
was a monk. This let him do
LOTS of experiments with the
peas!
Each trait had 2 options. This
was key because he could tell
if it was one way or the other.
VOCABULARY
• "Think! How the hell are you gonna think
and hit at the same time?"
HOMOZYGOUS
organism with two
identical alleles for
the same trait
(TT or tt)
HETEROZYGOUS
organism with two
different alleles for
the same trait
(Tt)
DOMINANT
allele that is expressed
when in the presence
of a recessive allele
(TT or Tt = tall)
RECESSIVE
allele that is expressed
only when
homozygous
(tt = short)
PHENOTYPE
physical
characteristics
(Tall, Brown)
GENOTYPE
the genetic makeup
(TT, TtHh)
GENE = Height
ALLELE = Tall, Short
Gene is represented by the letter “t”
Dominant = T
Recessive = t
Remember you need 2 copies of every gene!!!
How can we
determine what the
offspring are going
to be?
PUNNETT
SQUARES
Reginald C. Punnett
• Inventor of the
Punnett Square
PUNNETT
SQUARES
chart showing the
possible combination
of alleles in a cross
Punnett Squares
show the
probability of
getting a certain
type of offspring
THE PARENTS
GENOTYPES
• DAD = Tt (heterozygous)
• MOM = Tt (heterozygous)
PHENOTYPES
• DAD = Tall
• MOM = Tall
PUNNETT SQUARES
THE OFFSPRING
GENOTYPES
1TT:2Tt:1tt (1:2:1)
• TT (homozygous dominant)
• Tt (heterozygous)
• Tt (heterozygous)
• tt (homozygous recessive)
THE OFFSPRING
PHENOTYPES
3 Tall :1 Short (3:1)
• TT (tall)
• Tt (tall)
• Tt (tall)
• tt (short)
STUDENT DEMOS UP FRONT
• Do student demonstration with genotypes
• Do bag demonstration with beans tomorrow
Cross a homozygous
dominant with a recessive
(for height where T is
dominant and tall).
Find the genotype and the
phenotype
Cross a heterozygote with a
recessive (for height where T
is dominant and tall).
Find the genotype and the
phenotype
Cross a heterozygote with
another heterozygote (for
skin color where Black is B,
b = white).
Find the genotype and the
phenotype
Cross a heterozygote with
another heterozygote (for
nose size where big nose is N
and small nose is n).
Find the genotype and the
phenotype
• When you flip a quarter, what are the odds
that a coin turns up heads? What about
when you flip two coins at the same time,
what are the odds that both turns up heads?
• Coin Flip Lab
• Coin 1 Coin 2 HeadsTailsHeadsTails %
Heads% Tails% Heads% Tails
Test Cross
A cross between an
unknown and a
homozygous recessive
Example of a Test Cross
Unknown
Codominance
When a combination of the
dominant and recessive creates
a new phenotype. RR = red,
rr = white, and Rr = pink
Codominance
RR
Rr
rr
Codominance Cross
Codominance Cross
Sex Linked Trait
a trait that is found
on either the X or Y
chromosome
Hemophilia is an
example of a sex
linked trait.
Hemophilia
a disease where your
blood doesn’t clot.
Hemophilia only
occurs when all of the
X chromosomes have a
copy of the recessive
gene.
H
h
X X :female carrier
h
h
X X :female hemophiliac
H
X Y:normal male
h
X Y:hemophiliac male
SICKLE CELL ANEMIA
Difference between normal
cells & sickle cells
Sickle Cell
SS =
normal
Ss = carrier
(SC trait)
ss = sickle
cells
(lethal)
Sickle Cells tend to get stuck easily
in the circulatory system.
Why would African
American’s be so
much more likely to
have Sickle Cell?
Regular red blood cells
infected by malaria
PEDIGREE
chart that shows
the relationships
within a family
Pedigree Basics
• Males are squares, females are circles, and
unborn babies are triangles or octagons
• Shaded figures represent individuals with
the trait, a carrier could be 1/2 shaded
• Generations are numbered with roman
numerals (I, II, II, IV) from top to bottom
• People within generations are numbered
(1,2,3) from left to right
PEDIGREE HELP!!!!
200 B.C.
Humans “clone” trees by cuttings
1950
Humans clone frogs
1980’s
Humans clone mice!
1997
HUMANS CLONE SHEEP!!!
1998
Humans clone 8 copies of a cow!!!
20??
GENETIC
ENGINEERING
moving genes from one
chromosome of one
organism to the
chromosome of another
“Fat” Gene
CLONING
making an exact
copy of another cell
/ organism
Dolly—the first cloned sheep
Ian Wilmut,
the dude that
did it
Check out this short
movie that talks about
cloning…
A dividing cell
Read NYTimes Article
"Despite Warnings, 3 Vow to Go Ahead on Human Cloning"
a. What did three proponents of human cloning
announce on August 7, 2001?
b. Where did they make this announcement?
c. Why did some scientists at the symposium object
to the proponents' announcement?
d. Why did Dr. Alan Colman object to the research
by these proponents being done in secret?
e. According to the article, what was the consensus
among the panel and most of those who
testified before it?
Read NYTimes Article
"Despite Warnings, 3 Vow to Go Ahead on Human Cloning"
f. Who was "Dolly"?
g. What animals have been successfully cloned?
h. According to the article, what is involved in
cloning a human?
i. How did the three proponents say they would
address the possibility of genetic
abnormalities?
j. How did other experts at the symposium respond
to this statement?
k. Why do the proponents need to conduct their
research secretly?
•http://www.biology.arizona.edu/human_bio/activities/karyot
yping/karyotyping.html
•http://www.pathology.washington.edu/galleries/Cytogaller
y/cytogallery.html
•http://www.biology.iupui.edu/biocourses/N100/2k2humancs
omaldisorders.html
•http://www.biology.washington.edu/bsa/karyotypeS.html
•http://worms.zoology.wisc.edu/zooweb/Phelps/karyotype.html
AMNIOCENTESIS
A technique used to
determine the genetic
traits of a baby before
it is born
Klinefelter Syndrome
• Have male genitalia and internal ducts, but
underdeveloped testes
• Do not produce sperm
• Slight enlargement of the breasts
• 47,XXY
• 1 out of every 500 male births
Turner Syndrome
•
•
•
•
•
•
•
Has female external genitalia
Underdeveloped ovaries
Short (under 5 feed)
Webbed Neck
Broad, Shield-like chest
45,X
1 out of every 3000 female births
Cri-du-Chat Syndrome
• Partial monosomy (part of 1 chromosome is lost)
• Loss of about 1/3 of the short arm of chromosome
5
• Anatomical malfomrations (gastrointestinal and
cardiac complications)
• Mentally retarded
• Abnormal development of the larynx which makes
the baby’s cry sound like a cat’s cry
• 1 in 50,000 live births
Down Syndrome
•
•
•
•
•
•
•
•
•
BKA trisomy 21 (47, 21+); 3 copies of the 21st chromosome
Short
Small round heads
Protruding, furrowed tongues which cause mouth to remain partially
open
Retarded (IQ below 70)
Shortened life expectancy (<50)
Prone to reparatory disease and heart malformations
Have 15x higher chance of getting leukemia
Chance of having a baby with Down syndrome goes up as the mother
gets older
Guided Notes Mini-Clinical: 10pts
I
meant to start these backup again but got
caught up in the excitement of getting a
room.
 On
a clean sheet of paper answer the
following… you may use your notes
1.
2.
3.
4.
5.
How do the base pairs in DNA matchup?
What is the difference between DNA and
RNA?
How do transcription and translation differ?
Name 2 scientists that we talked about who
helped “discover” DNA
Draw the pathway from DNA to protein.
TRADE N GRADE


How do the base pairs in DNA matchup?
A-T, G-C
Pedigree Basics
• Males are squares, females are circles, and
unborn babies are triangles or octagons
• Shaded figures represent individuals with
the trait, a carrier could be 1/2 shaded
• Generations are numbered with roman
numerals (I, II, II, IV) from top to bottom
• People within generations are numbered
(1,2,3) from left to right