Download The Saga of the Earlobe Pedigree

The Epic Earlobe Pedigree
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Background Information
The story begins during World War I in the U.S. John Johnson had recently become a widower after his wife, Jane, and daughter,
Amy, were killed in a house fire. His daughter had unattached earlobes. He decided to sell his farm and become a soldier in the
war. He worked to the rank of general. After returning home after the war, he became good friends with the niece, Anne, of
another general. Five years later, he married her and they had two sons, Bob and Lee. While their sons were still young, John and
Anne became dissatisfied with the U.S. economy so they moved to Brazil. They lived in southern Minas Gerais, just north of Rio
de Janeiro, close to Barbacena. Before she left for Brazil, Anne’s uncle gave her a set of beautiful, gold earrings for her small,
attached earlobes. John and Anne lived a long, happy life in Brazil- in part because they shared so many characteristics, such as
earlobe appearance.
Soon after John and Anne arrived in Brazil, Ivan Kruger, fearing the rise of Nazism in Germany, moved to Brazil, as well as. Ivan
and his Italian wife, Paula, were not happy because Paula’s family did not accept her marriage to a German. Ivan was a merchant
with some money, so they decided to try and make a new life and fortune in Brazil. Both of the Krugers had unattached earlobes,
but their only daughter, Helena, had attached earlobes. They eventually settled in the state of Minas Gerais in the town of Belo
Horizonte.
The Johnsons found life in Brazil exciting, but the language was a challenge. They bought a large farm where they raised cattle.
Their family grew quickly as they had three daughters after they arrived in Brazil-Elizabeth, Mary, and Rachel—and another son,
Andrew.
Meanwhile, the Krugers were living happily in Belo and had two more children, Boris and Zelda. Boris married a German girl
from Parana (south of Sao Paulo) and they never had any children. Zelda married a man from Belo and they had no children. Ivan
and Boris exported emeralds across the world.
Bob Johnson married Maria, from Bahia. They operated a sugarcane plantation in Bahia. They had four girls. The first three had
unattached earlobes, but the youngest had attached. John and Anne’s middle daughter, Mary, married a sheep farmer, and they
had identical twin boys, Casey and Chris. At the age of three, one of the twins was attacked by a sheepdog, which bit off one of
his attached earlobes.
Many years later, Andrew Johnson met a beautiful lady from Belo named Helena Kruger. They soon married and had four
children- a boy, a girl, and two more boys. Their oldest, Anselmo, was much like his father. He moved to the Amazon to start a
trading center. He married an Arauaki Indian with attached earlobes. Their four children spent much time in the rainforest. The
oldest and youngest were boys, and the middle two were girls. Their second child, Annamika, was the only child with unattached
earlobes. Their youngest son, Mario, was a great hunter/ explorer. He was once attacked and lost both earlobes to arrow. He
escaped deadly peril, however, and married a distant cousin from the Arauaki tribe. She had dainty, attached lobes. They had five
children: three daughters followed by two sons.
Andrew and Helena’s second child, Claudia, married a businessman named Rico from Sao Paulo. They had a daughter, two sons,
and two more daughters. All of their children had unattached earlobes. Their youngest son, Enrique, married a German girl from
the city of Curitiba. Their three children, a boy followed by two girls, had unattached earlobes like their mother. Enrique’s
youngest, Gretchen, married a Canadian with attached earlobes. They had eight children—four girls followed by four boys. The
girls had earlobes like their father and the boys all had earlobes like their mother (just the opposite of the Brady Bunch).
Andrew and Helena’s middle son, Ian, looked identical to his grandfather Kruger, with the exception of his earlobes. He married a
Japanese immigrant, an only child, named Meiko, and they settled on a rose farm in Juiz de Flora. Their four children worked in
the business. They had a girl, a boy, a girl, and then a boy. The youngest, Emerson, married a girl from Lavras, named Monique,
who had unattached earlobes. Emerson and his wife became teachers and had a son followed by a daughter. Both had attached
earlobes, just like their Japanese great-grandmother. Not understanding basic Mendelian genetics, the kids were absolutely
stunned since neither of their parents nor any of their dad’s siblings had attached earlobes.
Andrew and Helena’s youngest, Daniel, met a nursing student in Sao Paulo named Carmen. They married soon after they both
graduated from the university. Both Carmen’s parents had unattached earlobes. Carmen was the oldest of six kids. The three girls
were older than the three boys. All had attached earlobes except Carmen and her youngest brother, Marcelino.
Marcelino married a girl named Lorena. They had a boy and a girl, both with unattached lobes like their mother. Their son,
Ricardo, married a girl named Suzanna and they had two girls and a boy. All three of Ricardo and Suzanna’s children envisioned
a world where some people would have many piercings. The son was sad because he didn’t have room for multiple earlobe
piercings since his earlobes were attached (unlike his sisters’), and he really wanted to express himself through body part. He
pierced his nose, eyebrows, and lip instead. His parents were not pleased.
Tasks and Analysis
1. Construct a complete pedigree on a separate piece of paper based on the above information. The
dominant trait, unattached earlobes, will be indicated by EE or Ee. The recessive trait, attached
earlobes, will be shaded. Next to (or above or below) each symbol, list the name of the person and
his or her genotype (even if it is E__). Recommendation: use a piece of blank, white paper and a
pencil and write small, leaving plenty of room for additions! This may require you to recopy your
pedigree into a neater version once you finish. When you finish, go back through the background
information and check your work!
2. One of the individuals on the pedigree must be adopted. Who is it and how do you know?
3. Predict the following:
a. Casey, who loves his earlobes, marries a woman with unattached earlobes. What can you tell
him about the likelihood that his offspring will have attached earlobes like him?
b. Elizabeth met Boris at the wedding of Andrew and Helena. They began to date, but she was
concerned about their earlobe differences. She broke off their engagement because she
wanted at least a chance of having kids with attached earlobes like hers and those of her
parents. She feared that since Boris had unattached, as did both of his parents, that it was
hopeless. Boris went on to marry later, but Elizabeth never did. She lived a life of “what
ifs?” and regret. What would you have told her based on your understanding of the earlobe
situation?
4. You are a geneticist working in a remote area of Venezuela. You’ve been brought in to determine the
cause of a disorder that is causing dermatological problems and multiple lipomas (fatty, benign
tumors). The remote area was settled by a small group of 30 individuals about 100 years ago. The
population has grown to around 1000 individuals, and there is a 12% rate of affliction with this
disease. The afflicted are spread evenly among males and females. Most every family has
individuals with the disease. The individuals are suspicious of you and your motives and are not
willing, at this point, to undergo invasive testing (including blood tests). Physical examinations,
however, will reveal the presence of the disease, and the population has agreed to physical exams.
a. Discuss why, if the disorder is genetic, there is such a high degree of occurrence in this
particular population.
b. How will you proceed in collecting and analysis of data?
c. Assuming that the disease has a genetic basis, can you definitively rule out any of the more
common modes of transmission (autosomal dominant, autosomal recessive, or sex-linked
recessive)? Discuss what you would expect to see for each mode of inheritance in your
answer.
d. Is it a certainty that you can solve this based on just the physical examination evidence?
Explain.