Pedigree Chart

A diagram that shows family connections between several

generations

What do the symbols mean?

= male

= female

= affected individual

= carrier

= mating

I

II

Offspring in birth order;I and II refer to generations

Identical Twins

Fraternal Twins

What is this called?

How is this trait passed on?Critical thinking - solve the puzzle

?

?

Autosomal, X-linked, Y-linked?

Expressed in both sexesin similar frequencies = autosomal

Dominant or recessive?

Expressed in many generations, only takes one allele to express it= dominant

Colorblindness

Mode of inheritance? Autosomal/X-Linked? (How do you know?)Is it dominant or recessive? (How do you know?)

1 2

3 4 5 6 7

8 9 10 11 12 13

http://colorvisiontesting.com/How does the world look to a color blind person?

Tell the condition of each person:Normal 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

Mode of inheritance? Autosomal/X,Y-Linked? (How do you know?)Is it dominant or recessive? (How do you know?)

Hairy Ears

Deafness in DalmationsIs 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)

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 mom’s dad (your maternal grandfather) as a predictor of baldness, not our own father.

Baldness

Female-Pattern Alopecia

Male-Pattern Baldness

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.

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.

The Story of Hemophilia

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.

Pedigree #1 Pedigree #2

Pedigree #3

Determine the model of inheritance

- Related to each other

autosomal dominant autosomal recessive

Sex-linked recessive

Pedigrees of two US families with high incidence of mesothelioma