Fundamentals of Genetics - Weebly

Workbook Answers Topic 1.2

Fundamentals of Genetics

1. a) probability b) F1 generation c) F2 generation d) phenotypic ratio

e) genotypic ratio

f) homozygous g) homozygous dominant h) homozygous recessive i) recessive

2. A Punnett square is a grid that shows the genotype of the parents and the possible genotypes of the offspring. It is used to determine the probability of inheriting a trait.

3.

b. homozygous dominant

c. recessive allele

a. dominant allele

Rr R RR Rr r Rr rr

f. offspring

d. heterozygous

e. homozygous recessive

4. The Punnett square shows a monohybrid cross.

5. a) Rr

d) 25% wrinkled seeds

b) round seeds

e) 1RR:2Rr:1rr

c) 75% round seeds

f) 3 round seeds:1 wrinkled seed

Dominant and Recessive

1. A recessive trait is expressed when two recessive alleles are present.

2. A dominant trait is expressed when one or two dominant alleles are present.

3. a) FF

b) Ff

c) ff

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Answers Topic 1. 2 1

4. a) 100% TT; 0% Tt; 0% tt 100% tall stem; 0% short stem

TT ? TT

T

T

T

TT

TT

T

TT

TT

Workbook Answers Topic 1.2

b) 25% YY; 50% Yy; 25% yy 75% yellow seed; 25% green seed

Yy ? Yy

Y

y

Y

YY

Yy

y

Yy

yy

c) 50% PP; 50% Pp; 0% pp 100% purple flower; 0% white flower

PP ? Pp

d) 0% RR; 0% Rr; 100% rr 0% round seed; 100% wrinkled seed

rr ? rr

P

p

r

r

P

PP

Pp

r

rr

rr

P

PP

Pp

r

rr

rr

5. a) 0% EE; 50% Ee; 50% ee b) 50% long eyelashes; 50% short eyelashes

e

e

E

Ee

Ee

e

ee

ee

2 Answers Topic 1. 2

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6 a) The dominant form of the gene is hairy toes (H).

b)

Pair 1

Pair 2

H

h

h

h

H

HH

Hh

h

Hh

hh

Pair 3

H

H

H

Hh

Hh

h

hh

hh

Pair 3

H

H

H

HH

HH

H

HH

HH

H

HH

HH

h

Hh

Hh

Pair 1: Hh and Hh Pair 2: Hh and hh Pair 3: HH and HH or HH and Hh

Workbook Answers Topic 1.2

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Answers Topic 1. 2 3

Workbook Answers Topic 1.2

Codominance and Incomplete Dominance 1. Complete Dominance: Genotype = Rr and Phenotype = red

Incomplete Dominance: Genotype = FRFW and Phenotype = pink Codominance: Genotype = FRFW and Phenotype = red and white

Complete Dominance

Incomplete Dominance

Genotype: RR Phenotype: red

Codominance

Genotype: FRFR Phenotype: red

Genotype: Rr Phenotype: red

Genotype: FRFW Phenotype: pink

Genotype: rr Phenotype: white

Genotype: FWFW Phenotype: white

Genotype: FRFR Phenotype: red

Genotype: FRFW Phenotype: red and white

Genotype: FWFW Phenotype: white

2. a) 25% HRHR; 50% HRHW; 25% HWHW b) 25% red; 50% roan; 25% white

d) Phenotypic Ratio: 1:2:1 e) 3 red, 6 roan, 3 white

c) Genotypic Ratio: 1:2:1 3. a) 0% FBFB; 100% FBFW; 0% FWFW

b) 0% black; 100% checkered; 0% white

4. Phenotypes of children: 50% Type A Blood; 50% Type B Blood; 0% Type AB Blood; 0% Type O Blood

5. Probability of Type O blood: 0%

6. Genotypes of the parents: AO and BO

4 Answers Topic 1. 2

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Workbook Answers Topic 1.2

7. a) Genotypes of the parents: FRFR and FWFW b) Genotype of the pink flowers: FRFW

c) Genotypes of the F2 generation: 25% FRFR, 50% FRFW, and 25% FWFW Phenotypes of the F2 generation: 25% red, 50% pink, and 25% white

8. Possible genotypes: 50% HBHW and 50% HWHW

9. Cross 1: purple flower ? blue flower (FRFB ? FBFB)

Cross 2: purple flower ? purple flower (FRFB ? FRFB)

Sex-Linked Traits

1. A sex-linked trait is a characteristic controlled by genes located on the sex chromosomes.

2. a) XhY

d) XHXh

b) XhXh

e) XHXH

c) XHY

3. a) 25% XHXH; 25% XHXh; 0% XhXh; 25% XHY; 25% XhY

b) 25% hemophiliac; 75% normal blood clotting ability

4. Probability of child with vision deficiency: 0%

5. Probability of child with vision deficiency: 25% 6. a) The genotypes of the parents are XDXd and XDY.

b) 25%

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Answers Topic 1. 2 5

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