Genetics of Selu
Summary: This lesson is an exploration of the genetics of corn, specifically a monohybrid cross
and the resulting pigmentation. Using Punnett squares, students predict the phenotype of
generations of corn and experiment to confirm their hypothesis.
Grade: 7
Subject area: science
Activity Time: 45 min
Setting: indoor
Skills: create, synthesize, analyze
Vocabulary:
agriculture: the science or practice of farming, including cultivation of the soil for the growing of
crops and the rearing of animals to provide food and other products
producer: green plants that synthesize food through the process photosynthesis
native plant: occurs naturally in a particular region, habitat, or ecosystem
annual plant: completes its life cycle from germination to the production of seed, within one year
and then dies
monocot: having one cotyledon, or food stores, within one seed
homozygous: having identical pairs of genes for any given pair of hereditary characteristics.
(PP,pp)
heterozygous: having two different alleles for a single trait. (Pp)
phenotype: an organism's expressed physical traits. Phenotype is determined by an individual's
genotype and expressed genes, random genetic variation, and environmental influences.
genotype: is the information contained within two alleles, the genetic makeup of an organism
that results in some of the physical characteristics of that organism. Genotypes can only be
determined by biological tests, not observations.
purebred: an offspring of unmixed breeding
hybrid: an offspring of two animals or plants of different races, breeds, varieties, species, or
genera
Materials:
Computer and projector for Prezi
Corn for comparison (several ears of various colors, rows numbers, etc)
Genetics of Selu student worksheet (1 per student)
16 ears of purple:yellow corn
16 black wet-erase markers
16 blue wet-erase markers
Cherokee historic photos of corn being processed
Objectives:
Students will be able to…
Collect and organize data from genetic crosses.
Predict patterns of inheritance given relevant data.
NC Essential Standards
7.L.2 Understand the relationship of the mechanisms of cellular reproduction, patterns of
inheritance and external factors to potential variation among offspring.
7.L.2.1 Explain why offspring that result from sexual reproduction (fertilization and
meiosis) have greater variation than offspring that result from asexual reproduction
(budding and mitosis).
7.L.2.2 Infer patterns of heredity using information from Punnett squares and pedigree
analysis.
7.L.2.3 Explain the impact of the environment and lifestyle choices on biological
inheritance (to include common genetic diseases) and survival
Background:
From the earliest times in Cherokee history, the raising of corn was interwoven with the spiritual
beliefs of the people. In fact, the Cherokee name for corn, “Selu”, is also the name for the First
Woman in the Cherokee creation stories. Though it had been grown in its first forms for more
than a thousand years, in the Mississippian Period a new variety of corn with more kernels
emerged called eastern flint. Corn combined with beans and squash became known as “The 3
Sisters.” These crops provided the means by which Mississippian Indians were able to increase
their population and their leisure time. They also refined their planting, cultivating, and
harvesting techniques. They used a method called “hilling,” piling dirt around the base of the
cornstalk to provide drainage. Cherokees also had an ingenious method of pest control. They
hung gourds around their garden to attract purple martins. Nesting in the gourds, these birds,
known to consume large quantities of insects, would aggressively defend their territory against
crows and blackbirds, both of which could destroy newly planted corn. (See additional handouts
for further background information.)
Procedures:
1. Pass out historic photos and ask students:
a. What do the photos have in common?
b. Put them in order the way you think corn is processed.
c. Have students justify and discuss answers. Text on the back of the photos can
help support answers.
2. Lead students through the Prezi presentation.
Extension Activities:
Visit one of the many gardens in the area or contact a local farmer to visit the classroom.
Plant a trip to Great Smoky Mountains National Park to visit the Mountain Farm Museum and
Mingus Mill for information on growing and processing corn during the late 1800’s in
Appalachia.
Genetics of Selu
Prezi Notes for Presenter
Slide 1: Genetics of Selu: Home slide
Selu, (pronounced shay-loo) is the Cherokee word for corn. When we shop at the grocery store,
the corn we buy in the produce section or in a can is yellow or white. But the corn you see in this
photo, and at the Annual Cherokee Indian Fair, and in produce stands everywhere in the fall is
many, many different colors. But how does one ear of this multicolored flint corn form kernels of
so many different colors? Today we are going to talk about how farmers use their knowledge of
genetics to produce corn that has the colors they want to see. In other words, we will learn how
they use their knowledge of genotype to produce the desired phenotype…and win a ribbon at the
fair!
Slide 2: What is corn? Ask students if they know any of the words listed on this slide that
describes the characteristics of corn. Let them answer, and clarify or support as needed. (See
vocabulary list above for exact definitions but allow for discussion before just giving
definitions.)
“Zea mays” (not listed in the above definitions) is the scientific name for corn/ maize.
Slide 3: Corn and the Cherokee: The beginning of Cherokee culture is identified with the
cultivation of corn by the native people in the Southern Appalachians more than a thousand years
ago.
3 Sisters: Corn, beans and squash, known as the 3 sisters, are planted together for several
reasons. The corn stalk provides structure for the climbing vines of the bean plants. The bean
plants add beneficial nitrogen to the soil. The large-leaved, low-growing squash plants provide
ground cover that keeps away weeds. These 3 plants were the basis of the Cherokee diet during
the Mississippian Period. These crops are still grown together today.
Daily Use: What are some ways corn was used in the early history of the Cherokee? What are
ways corn is used now?
Deer Lure: Do we have any hunters in this class? Both in ancient times and now, corn was often
used as a deer lure. During the Mississippian Period the stalks around the outside of the field
were left standing in winter. One reason may have been to attract deer and allow hunters to stay
closer to home in the coldest months.
Corn Mother: The Cherokee folktale of Selu, Corn Mother, First Woman, describes her abilities
to rub her stomach and fill a basket with corn and then rub under her arms and fill a basket with
beans.
3a: This picture shows a drawing from the Museum of the Cherokee Indian of Selu. You
can see the beans coming from her armpits and the corn on her stomach, as told in the
folktale.
Slide 4: How does corn reproduce? Corn is a flowering plant. It reproduces like other
flowering plants, by passing pollen from the male to the female part of the plant.
4a: When we think of “corn” we are usually just thinking of this part of the plant.
However, this is just the female part of the plant. Under the husks, each of these kernels
is attached to one of the “silk” threads you see protruding from the top of the ear.
4b: The tassels on the top of the plant are the male part of the plant. When pollen from
the tassels land on the silk, they fertilize the seed. Because each silk is only attached to
one kernel, then each kernel has the possibility of inheriting a different genotype.
Slide 5: They meet…So how do we get multi colored corn? Do the purple and yellow meet and
fall in love? Read and do STUDENT WORKSHEET #1-2 together.
Slide 6: F1: First Generation Selu: Read and do STUDENT WORKSHEET #3-5
Slide 7: F2: Second Generation Selu: Read and do STUDENT WORKSHEET #6-9
Slide 8: Is selu still important to Cherokee people? Corn is still grown in gardens across the
Qualla Boundary, and in fact Kituwah, the mothertown of the Cherokee, is surrounded by corn
being grown by Cherokee people. To wrap up here is a video made by the students working in
the Cherokee Youth Garden telling all about the life cycle of corn being grown at Kituwah.
Selu Corn Mother When the boys got home they were very tired and hungry and asked their mother for something to eat. "There is no meat," said Selu, "but wait a little while and I'll get you something." So she took a basket and started out to the storehouse. This storehouse was built upon poles high up from the ground, to keep it out of the reach of animals, and there was a ladder to climb up by, and one door, but no other opening. Every day when Selu got ready to cook the dinner she would go out to the storehouse with a basket and bring it back full of corn and beans. The boys had never been inside the storehouse, so wondered where all the corn and beans could come from, as the house was not a very large one; so as soon as Selu went out of the door the Wild Boy said to his brother, "Let's go and see what she does." They ran around and climbed up at the back of the storehouse and pulled out a piece of clay from between the logs, so that they could look in. There they saw Selu standing in the middle of the room with the basket in front of her on the floor. Leaning over the basket, she rubbed her stomach­­​
so​
­­and the basket was half full of corn. Then she rubbed under her armpits­­​
so​
­­and the basket was full to the top with beans. The boys looked at each other and said, "This will never do! Our mother is a witch! If we eat any of that it will poison us! We must kill her!" When the boys came back into the house, she knew their thoughts before they spoke. "So you are going to kill me?" said Selu. "Yes," said the boys, "you are a witch." "Well," said their mother, "when you have killed me, clear a large piece of ground in front of the house and drag my body seven times around the circle. Then drag me seven times over the ground inside the circle, and stay up all night and watch, and in the morning you will have plenty of corn." The boys killed her with their clubs, and cut off her head and put it up on the roof of the house with her face turned to the west, and told her to look for her husband. Then they set to work to clear the ground in front of the​
​
house, but instead of clearing the whole piece they cleared only seven little spots. This is why corn now grows only in a few places instead of over the whole world. They dragged the body of Selu around the circle, and wherever her blood fell on the ground the corn sprang up. But instead of dragging her body seven times across the ground they dragged it over only twice, which is the reason the Cherokees still work their crop but twice. The two brothers sat up and watched their corn all night, and in the morning it was full grown and ripe. Names________________________________________________ Date_______________ Period _______
Genetics of Selu
In these activities you will investigate phenotypes of corn that are expressed in the seed. You will be given ears
of corn for your investigation. Each seed on an ear of corn results from a separate fertilization event and thus
represents an offspring.
1. We begin with the parent plants. In this case one plant produces purple ears of corn, the dominant color.
The other plant produces yellow ears of corn, the recessive color, considered and absence of pigment.
Both plants are homozygous. Below, draw a Punnett square to represent the possible offspring
resulting from this cross. These offspring will be known as First Generation (F1).
Homozygous
Homozygous
Dominant
Recessive
2. What is the genotype of the F1? ______________________________________________________
3. Using the information you recorded on the first page, and your knowledge of genetics, draw in the space
below a Punnett square showing the results of crossing your F1 generation to produce the next
generation of offspring, F2.
4. From your completed Punnett square, give the phenotypes and their expected ratios for the F2 offspring.
5. Using your completed Punnett square make a hypothesis about the inheritance of phenotypes. Using
your hypothesis, predict what you will find in the F2 offspring.
6. You will now test your hypothesis and prediction made in step 5. You will get an ear of corn from the
cross you diagramed in step 3 for F2. Working in groups, count and record in Table 1 the number of
grains of each phenotype.
To make the count, use the black and blue markers for the two phenotypes expressed. While counting,
mark each grain of one phenotype with the blue marker. Record your total. As you count the other
phenotype, mark each grain with the black marker.
Table 1: F2 Phenotype Count for _____________________________ x__________________________
Phenotype
Team Count
Total
Total
Team total for all phenotypes counted
Class Count
Total
Class total for all phenotypes counted
Total
7. To determine the expected counts, take the total class count, divide by 4 (number of combinations), and
then use the ratios determined in step 4 to predict how many of each phenotype should be expected.
Phenotype_____________________________________ expected count_______________
Phenotype_____________________________________ expected count_______________
8. Compare the class’s actual counts from Table 1 with your calculated expected counts. Are the actual
counts different from the expected counts? If so, explain why.
9. Do the results tend to confirm or disprove your hypothesis as stated in step 5? Explain your answer.