Hairy Heredity

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Grade 6. Science Process—2.1;. 4.1,2; 5.3,4. Math Process—1.6; 2.1;. 4.1. Math —5.1 ... Give each student a copy of the activity worksheet and a coin. —Instruct ...
Hairy Heredity Skills:

Life Science, Math

Objective: Students will flip coins to demonstrate how parents pass genetic traits to their offspring through heredity and the difference between dominant and recessive genes, and how they interact. Background

Agriculturalists have pioneered the study of genetics and heredity. For centuries farmers and ranchers have selected plant varieties and livestock for specific traits. Plant breeders select plant varieties which produce more seed or fruit. Livestock producers select animals with specific traits such as increased milk production, ample muscle mass or structural correctness. Selecting for these traits has allowed agriculturalists to produce a higher quality and more abundant food supply. Heredity is the passing on of traits from parents to offspring. Most plants and animals have two of every kind of gene, one from their mother and one from their father. Only one gene from each parent is passed to each offspring for a particular trait. There are different forms of a gene that are referred to as alleles. Alleles are forms of the same gene with small differences in their DNA sequence. These small differences contribute to each person's unique physical features. Some alleles are dominant while others are recessive. Dominant genes overpower recessive genes and are always expressed in offspring. Recessive genes are only expressed in offspring if both parents contribute a recessive gene. In human eye color, the gene for brown eyes is dominant and the gene for blue eyes is recessive. Therefore, if the offspring receives a brown eye gene from either parent, the offspring will have brown eyes. The offspring would have to receive a blue eye gene from each parent to have blue eyes. The following diagram is a Punnett square which illustrates all the possible combinations of two gene sets Bb and Bb and the resulting genetic traits. B is the dominate gene for Brown eyes b is the recessive gene for Blue eyes. Punnett square boxes show the possible combinations of genes that an offspring may receive from its parents. Punnett Square Bb X Bb Parent’s Eye Color

B 6 (Brown Gene)

b 6 (Blue Gene)

B (Dominant Trait) 4

BB = Brown Eyes

Bb = Brown Eyes

b (Recessive Trait) 4

Bb = Brown Eyes

bb = Blue Eyes

http:www.agclassroom.org/ok

P.A.S.S. Grade 5

Science Process—2.1; 4.1,2; 5.3 Math—2.1cd,2a

Grade 6

Science Process—2.1; 4.1,2; 5.3,4 Math Process—1.6; 2.1; 4.1 Math —5.1

Grade 7

Science Process—2.1; 4.1; 4.2; 5.3 Life Science—3.1, 2 Math—2.2c; 5.1,3

Vocabulary

agriculturalist—someone involved in the science, art, and business of cultivating the soil, producing crops and raising livestock. allele—one of two or more alternative forms of a gene that controls the same inherited characteristic. DNA (deoxyribonucleic acid)—molecule that contains genetic information and is located in the nucleus of every cell inside an organism. gene—The basic unit of heredity that serves as a blueprint for each protein product produced in the human body; humans have over 30,000 genes. heredity—the passing on of traits from parents to offspring. Punnett Square—diagram used by scientists to help them to figure out how inherited traits (characteristics) will be distributed. trait—an inherited distinguishing feature or characteristic of an organism.

Probability is the chance that something will happen. Using the above Punnett square box, there is a 75 percent chance of an offspring having brown eyes if both parents have both dominate and recessive genes. There is a 25 percent chance of the offspring having blue eyes. This simple illustration demonstrates how the genetics of one gene functions. Humans, plants and animals have multiple genes which have complex interactions to determine offspring traits.

Math and Science 1. Brainstorm to find student knowledge of the transfer of genetic traits from parents to offspring. Share background material. 2. Give each student a copy of the activity worksheet and a coin. —Instruct students to flip the coin to determine which traits the mother will pass on to her offspring. If the coin lands on heads, the students should circle the dominant trait. If the coin lands on tails, the students should circle the recessive trait. —Have students repeat this process for all eight traits from the mother and father. —Once all the traits have been randomly selected from the mother and father, transfer the selected traits to the Genetic Trait Worksheet. —Circle the appropriate genetic trait which will be expressed in the offspring. 3. Hand out the “Smiley Face Worksheet,” and have students draw and color a smiley face that expresses all the randomly selected genes. —Are all the faces the same? How are the faces different? Why? —Count across the room the number of smiley faces with brown eyes. Is it 75 percent of the faces, as the Punnett Square predicted? Do the same for the other traits. 4. Repeat the genetic activity and compare the results with this activity. Are the results the same? Is the percentage of blue eyes the same? Other traits? 5. Develop a Punnett square diagram for the other traits. Why is there a 50 percent chance of the offspring being a girl? 6. . Compare student’s characteristics around the room. Do 75 percent of the students have brown eyes? What percentage of student’s eyes are blue or green?

Oklahoma Ag in the Classroom is a program of the Oklahoma Cooperative Extension Service, 4–H Youth Development, in cooperation with the Oklahoma Department of Agriculture, Food and Forestry and the Oklahoma State Department of Education. Oklahoma Ag in the Classroom Oklahoma 4-H Programs 205 4-H Youth Development Oklahoma State University Stillwater, OK 74078 405-744-8889 http://www.agclassroom.org/ok

http://www.agclassroom.org/ok

Hairy Heredity

Name ______________________________________________________________

Use the flip of a coin to determine which genes your offspring will carry. Flip a coin to determine which genetic traits each parent will pass on to their offspring. If the coin flip lands on heads select the dominate trait. If the coin lands on tails, select the recessive trait.

FATHER’S TRAITS

MOTHER’S TRAITS

Flip coin and circle selected trait.

1. face shape

heads tails dominant recessive R

s

1. face shape

B

b

3. eye color

4. mouth shape

S

f

6. skin color

Y

2. eye shape 3. eye color

5. nose shape 7. hair

8. male/female

R

B

H X

o

2. eye shape

heads tails dominant recessive R

R

s

o

B

b

4. mouth shape

S

f

o

6. skin color

Y

o

X

8. male/female

l

b

5. nose shape 7. hair

B

H X

Produced by Oklahoma Cooperative Extension Service, Division of Agricultural Sciences and Natural Resources, OSU, inn cooperation with the Oklahoma Department of Agriculture, Food and Forestry and the Oklahoma State Department of Education, 2005.

l

b Y

Genetic Trait Worksheet

Name ______________________________________________________________

sample trait 1. face shape 2. eye shape 3. eye color 4. mouth shape 5. nose shape 6. skin color

mother’s traits T

father’s traits t

possible trait combinations Circle appropriate trait.

tall TT

round RR

8. male/female

short tt

round Rs

square ss

brown BB

brown Bb

blue bb

big BB

big Bl

round RR

smile SS

round Ro

oval oo

smile Sf

frown ff

yellow YY

yellow Yo

orange oo

male Xy

female XX

n/a

hairy HH

7. hair

tall Tt

hairy Hb

Produced by Oklahoma Cooperative Extension Service, Division of Agricultural Sciences and Natural Resources, OSU, inn cooperation with the Oklahoma Department of Agriculture, Food and Forestry and the Oklahoma State Department of Education, 2005.

little ll bald bb

Smiley Face Worksheet

Name ______________________________________________________________

1. face shape round / square

Draw and color the offspring’s smiley face Add details to identify your smiley as a boy or girl.

2. eye shape round / oval

3. eye color brown / blue

4. mouth shape smile / frown

5. nose shape big / little 6. skin color yellow / orange 7. hair hairy / bald

8. male/female boy / girl

offspring’s name____________________

Produced by Oklahoma Cooperative Extension Service, Division of Agricultural Sciences and Natural Resources, OSU, inn cooperation with the Oklahoma Department of Agriculture, Food and Forestry and the Oklahoma State Department of Education, 2005.