Transcript Genetic Disorder Template

Cystic Fibrosis
Ventura Simmons
1/29/2010
Period: 6/7
Summary
 Cystic Fibrosis mainly affects 2 of our
many systems: -Respiratory, and -Digestive
 In these systems our airways, lungs
(respiratory), stomach, colon, and intestines
(digestive)
 These organs are affected by this disease
because Cystic Fibrosis causes a change in
the properties of the mucus that coats the
inside of these organs, and this mucus aids
the organs in surviving without it it’d be a
lot like a teenager without electronics.
More Symptoms
 ･ May have a delay (more than 48 hours after birth)
in the passing of meconium(their first stool) ･ May
have foul-smelling, pale, and greasy stools ･ May
lose weight (because of difficulty absorbing nutrients)
･ May appear out of breath ･ May have frequent
wheezing ･ May have a persistent cough that
produces thick mucus ･ May have frequent
respiratory infections, such as pneumonia and
bronchitis ･ May have stunted growth (because of
chronic malnutrition from difficulty absorbing
nutrients) ･ May have abnormally salty sweat ･ May
become easily dehydrated ･ May have nasal
polyps(fleshy growths inside the nose) People with
cystic fibrosis may also experience liver disease,
diabetes, inflammation of the pancreas, and
gallstones.
QuickTime™ and a
TIFF (Uncomp resse d) de com press or
are nee ded to s ee this picture.
Chromosome 7
Quic kTi m e™ a nd a
TIF F (U nc om pre s s ed ) dec om p res s o r
are need ed t o s e e th is p ict ure.
Recessive
 This Disease is Recessive meaning you need to get
the gene from both parents to obtain it fully just like
blue eyes you need a blue eye gene from both
parents to have blue eyes so if both parents have
blue eyes you will just like if both parents have
Cystic Fibrosis their child will.
Explain what alleles are.
How many alleles does each person have per gene
Where they come from
How we represent recessive or dominant alleles
-RR, rr, Rr
What is dominance and recessiveness?
Sex linked (x-linked) is represented with XR, or Xr, or Y
Make a punnett square to demonstrate the probability
per child depending on the parents
Make more than one punnett square. Parents determine the ratio of probability of
offspring having the genetic disorder. Explain(see below) to the class how the punnett
square works.
Female is on the left and father is represented on the top.
*** Each punnett square represents the probability PER CHILD. Not all of the
children parents may have. ***
•homozygous dominant
•heterozygous dominant
•homozygous recessive
Use the same punnett square model to…
Explain probability using:
Ratios
(must equal 4 because there are 4 possibilities)
homozygous dominant:heterozygous dominant:homozygous recessive
1
1GG
:
:
2
2Gg
:
:
1
1gg
Percentages
(must equal 100 because there are 4 possibilities 25% each)
homozygous dominant:heterozygous dominant:homozygous recessive
25%
:
25%GG :
50%
50%Gg
:
:
25%
25%gg
Use the same punnett square to use as your
model to explain…
•What these letter mean! GG? Gg? gg?
If G represents the dominant allele GREEN and g represents the recessive allele
•Phenotype (what you SEE)
yellow, then we can assume that:
GG= GREEN
Gg= GREEN (yellow gene carrier)
gg = yellow
•Genotype (what
is in the GENES)
GG= Homozygous dominant (GREEN)
Gg= Heterozygous dominant (GREEN)
gg = homozygous recessive (yellow)
Use the same punnett square model to…
Explain Genotype and Phenotype probability using:
•Phenotype
-Ratios- 3 GREEN : 1 yellow
- Percentages- 75% GREEN : 25% yellow
•Genotype
- Ratios- 1GG : 2 Gg : 1 gg
- Percentages- 25% GG: 50% Gg : 25%gg
Student Practice
Punnett Square Practice
You provide genes for the students:
only parents and student fill in the box genotypes
and phenotypes
Genotype:
Ratio:
Percentage:
Phenotype:
Ratio:
Percentage:
-When the students are finished, ask
them to share their answers with you.
Use the custom animation option to hide
the answers until student
theirs with you.
s have shared
Lastly, a 3 generation hypothetical Pedigree
Autosomal Dominant
Circle = female
Square = male
All White= homozygous recessive gene, person is
fine, has 2 copies of the “healthy” gene
All Green= homozygous dominant, person have
disorder and 2 copies of the “bad” gene
Half Green/Half White= because this is a
dominant disorder (rules of dominance), the
person has the disease and only has one copy of
the “bad” gene and one copy of the “healthy”
gene.
Autosomal Recessive
White= Person is fine. May possibly
carry the recessive “bad gene.” Can
have one “health” and one “bad” gene
of two “healthy genes.”
Black= Person is affected. Has 2
“bad” genes.
X-linked
Color gene is “bad” on x chromosome
Color gene is “healthy” on x chromosome
Color gene is “healthy” on x chromosome
One gene is “bad”, one gene is
“healthy” on the x chromosome
Female is fine.
3 generations, (I: two parents II: 3 children and two spouses III: 4 children, any combo
( explain how to READ your punnett square)
Student Practice
(you provide generation I, 2, and 3)
Show a pedigree like this, but you fill in the rest using a different sample than the previous page.
You choose male and female, who is married to who (you have to add 2 spouses, and who has children in the
Generation III.
I
II
Example:
***Make a key: circle=
square=
shaded in=
not shaded in=
half shaded in=
III
Example:
***Ask 3 questions (type them on this page)
to make sure the students can analyze a
pedigree. (NO yes/no answers) 
1.
2.
3.