Investigating+Inherited+Traits+Lab PDF

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Sa'maiya Patton

6/22/21

Introduction to Genetics

Investigating Inherited Traits Introduction

Problem How are traits inherited?

Explain to the students that the actual combination of genes is much more complicated than is indicated by this investigation. Some of the traits result from multiple alleles. In order to simplify the investigation, assume that all of the traits used are the result of the combination of two alleles, or an allele pair.

Pre-Lab Discussion Read the entire investigation. Then, work with a partner to answer the following questions. 1. What does a single side of a double-sided coin or disk represent?

Each single side of a coin or disk represents one of two possible alleles.

2. What is the probability, in percent, that a single coin toss will result in heads? In tails?

© Prentice-Hall, Inc.

The probability that a single coin toss will result in either heads or tails is 50 percent. There is a 50/50 probability

3. Why is a coin toss a good way to represent allele combinations that occur in nature? A coin toss isofaalleles goodinway tooccurs represnt the allele becasue flipping a The combination nature by chance, as doescombinations the result of a coin toss. coin is not predictable.

4. For the traits explored in this lab, do all heterozygous pairs of alleles produce an intermediate phenotype? No,forfor some thelisted, traitsheterozygous listed, heterozygous pairs producephenotype. only the dominant No; some of theof traits pairs produce only the dominant phenotype. 5. Can you accurately determine an organism’s genotype by observing its phenotype? Explain your answer. Although knowing an organism’s genotype would allow one to predict its phenotype, some phenotypic traits can

knowing an organism's genotype would allow one to predict its phenotype, some phenotypic traits can be the result of either homozygous or heterozygous combinations of alleles.

Materials (per group) 3 textbooks 2 coins

Procedure

male. Remember that there are two genes per trait.

allele and tails will represent the recessive allele.

space on page 111.

108 Biology Laboratory Manual A/Chapter 11

© Prentice-Hall, Inc.

should be flipped only once for each trait.

Name______________________________

Traits

Date ______________

Dominant (both heads)

Hybrid (one head, one tail)

Recessive (both tails)

round RR

round Rr

Square rr

present CC

present Cc

absent cc

curly HH

wavy Hh

straight hh

present WW

present Ww

absent ww

close together EE

medium distance Ee

far apart ee

almond AA

almond Aa

round aa

straight SS

straight Ss

slant upward ss

large LL

medium Ll

small ll

Shape of face

Cleft in chin

Texture of hair

Widow’s peak

Spacing of eyes

Shape of eyes

Position of eyes

Size of eyes

© Prentice-Hall, Inc.

Figure 1

Biology Laboratory Manual A/Chapter 11 109

Traits

Dominant (both heads)

Hybrid (one head, one tail)

Recessive (both tails)

long LL

long Ll

short ll

bushy BB

bushy Bb

fine bb

not connected NN

not connected Nn

connected nn

large LL

medium Ll

small ll

thick TT

medium Tt

thin tt

large LL

medium Ll

small ll

large LL

medium Ll

small ll

present FF

present Ff

absent ff

present DD

present Dd

absent dd

Length of eyelashes

Shape of eyebrows

Position of eyebrows

Size of nose

Shape of lips

Size of ears

Freckles

Dimples

Figure 1 continued

110 Biology Laboratory Manual A/Chapter 11

© Prentice-Hall, Inc.

Size of mouth

Data Table for Your Baby Trait

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.

Sex Face shape Cleft chin Hair type Widow’s peak Eye spacing Eye shape Eye position Eye size Length of eyelashes Eyebrow shape Eyebrow position Size of nose Shape of lips Size of ears Size of mouth Freckles Dimples

Baby’s Name

Dad’s

Mom’s

gene

gene

Baby’s genotype

Baby’s phenotype

X X

X X X

X X

X X X X X X X X X X

XX

Baby’s total genotype: ______________________________________________________________

Describe what your baby will look like in words (their phenotype):

5

My baby would have curly hair, straight hairline and dimples

Analysis and Conclusions Answer the following questions on a separate piece of paper using complete sentences. 1. Calculating What percent chance did you and your partner have of “producing” a male offspring? A female offspring? Explain your answer. It would be a 50% chance of either sex. the mom donates one of her two X chromosomes, the dad will only donate either the X or Y chromosome. Either if the offspring receives the X/Y (50,50 chance) that determines the sex of the child 2. Predicting Would you expect the other pairs of students in your class to have an offspring completely similar to yours? Explain your answer.

No, because the probability of our whole class getting the same traits is very rare. 3. Inferring What are the possible genotypes of the parents of a child who has wavy hair (Hh)?

The possible genotypes of the parents child having wavy hair is HH X hh 100% or HH X Hh 50% or Hh X Hh 50% or(Hh X hh 50% 4. Classifying List all the traits in this investigation that showed incomplete dominance.

5. Drawing Conclusions Do you think that anyone in your class has all the same genetic traits that you have? Explain your answer.

no, not everyone has the same parents as me so they are less likely to have the same genetics as me. 6. Drawing Conclusions How might it be possible for you to show a trait when none of your relatives shows it?

It can be carried to you when the chromosomes combine even if the parents don't possess the same trait. It can skip and be dominant for you, so you would be able to see it in your genetic make up....