Pedigree Chart

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Pedigree Chart

• A diagram that shows family connections between
  several generations

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What do the symbols mean?
male
female
Offspring in birth order I and II refer to
generations
carrier
affected individual
Identical Twins
mating
Fraternal Twins
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Expressed in both sexes in similar frequencies
autosomal
What is this called?
Expressed in many generations, only takes one
allele to express it dominant
Autosomal, X-linked, Y-linked?
Dominant or recessive?
?
?
How is this trait passed on?
Critical thinking - solve the puzzle
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Colorblindness
Hairy Ears
Mode of inheritance? Autosomal/X,Y-Linked?
(How do you know?)Is it dominant or recessive?
(How do you know?)
Mode of inheritance? Autosomal/X-Linked?
(How do you know?)Is it dominant or recessive?
(How do you know?)
Tell the condition of each personNormal color
vision, Carrier (which means that person has
normal color vision, but they can pass it on to
their children through their X-sex chromosome)
Colored Blind
http//colorvisiontesting.com/ How does the world
look to a color blind person?
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Deafness in Dalmations
Is this trait sex-linked or autosomal? (How
do you know?)Is it dominant or recessive?
(How do you know?)Where is inbreeding
occurring?What impact does inbreeding have on
the passing of such a trait? (Hint look at
the offspring)
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Baldness
Male-Pattern Baldness
Female-Pattern Alopecia
1. What is the mode of inheritance for this
trait? X-linked, y-linked, or autosomal?
(Tell how you know.) 2. Is it dominant or
recessive? (Tell how you know.) 3. How can
females get Alopecia? Tell what has to
happen regarding the gene.
NEW YORK (Reuters Health) - Researchers in
Germany have found that variations in a gene
related to male sex hormones may be at the root
of male-pattern baldness, the most common form of
hair loss. The culprit is the androgen receptor
gene, and it dwells on the X chromosome, which
all men inherit from their mothers. So look at
your moms dad (your maternal grandfather) as a
predictor of baldness, not our own father.
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The Story of Hemophilia
Late in the summer of 1818, a human sperm and egg
united to form a human zygote. One of those
gametes, we don't know which, was carrying a
newly mutated gene. a single point mutation in a
nucleotide sequence coding for a particular amino
acid in a protein essential for blood clotting.
The zygote became Queen Victoria of England and
the new mutation was for hemophilia, bleeder's
disease, carried on the X chromosome. A century
later, after passing through three generations,
that mutation may have contributed to the
overthrow of the Tsar and the emergence of
communism in Russia. Victoria passed the gene on
to some of her children and grandchildren,
including Princess Alexandra, who married
Nicholas II, Tsar of Russia, in 1894. By 1903,
the couple had produced four daughters. The next
year, the long awaited male heir appeared - His
Imperial Highness Alexis Nicolaievich, Sovereign
Heir Tsarevich, Grand Duke of Russia. From his
father, the baby Alexis inherited the undisputed
claim to the throne of all the Russias. From his
mother, he inherited an X chromosome carrying a
copy of the mutant gene for hemophilia. Soon
after his birth, signs of Alexis' mutant gene
appeared. At six weeks, he experienced a bout of
uncontrolled bleeding and by early 1905 the
royal physicians had concluded that he was
suffering from hemophilia.
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Questions 1. What is hemophilia? 2. What
chromosome is this genetic disease carried on? 3.
Who contracted the disease? (Tell how you
know.) 4. Why did they contract it and not others
of same gender,or the other gender? 5. What was
the average lifespan of those who died from it?
Why do you think that is? Contrary to popular
belief, inbreeding does not result in "monstrous"
offspring. Marrying close relatives, as often
occurred in royal families did increase the
chances that recessive harmful alleles (like
hemophilia) would be inherited. Inbreeding has
caused many breeds of dogs to have harmful
genetic traits. Dalmations are often deaf, and
other dog breeds have high frequencies of
epilepsy, blindness, and hip dysplasia. It is
true, that mutts are often hardier and have less
health problems.
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Determine the model of inheritance
autosomal dominant
autosomal recessive
Pedigree 2
Pedigree 1
Sex-linked recessive
Pedigree 3
- Related to each other
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Pedigrees of two US families with high incidence
of mesothelioma