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Biology lab homework Dragon Genes http://www.concord.org/stem-resources/modern-g

ID: 62987 • Letter: B

Question

Biology lab homework

Dragon Genes

http://www.concord.org/stem-resources/modern-genetics

BLY 121L - Take Home Assignment

Due: Start of class time – At the start of class next week

Answers MUST be…

Complete ALL 4 modules:

1. Intro & Rules

2. Meiosis

3. Pedigree and Genes

4. The Plates Problem

Complete and answer all of the questions from each module.

Introduction

Breed dragons to yield several offspring and develop a chart for all of the phenotypic characteristics you observe.

What are the traits exhibited by your dragons?

**YOU MUST TURN IN YOUR COMPLETED CHART AND IT MUST BE LEGIBLE!

Rules

Dominance and Recessive Traits

What is the chromosome number (“n”) for the dragons?

Which trait(s) exhibit incomplete dominance?

What does it mean for a trait to be incompletely dominant?

No allelic combination is described as being heterozygous recessive. Why do you think this is the case?

Some Traits are Sex-linked

Which dragon trait(s) is/are sex-linked?

How do sex-linked traits differ from autosomal traits?

Color and Lethal Combinations

Describe how the inheritance of color is different from that of horns and/or wings.

On which chromosome is the lethal combination exhibited? What is the lethal combination?

Meiosis

What is the phenotype of your new dragon?

Which traits are inherited from the mother dragon? AND Which traits are inherited from the father dragon?

Were any traits expressed by the offspring that differed from either or both of the parents? If so, what were they?

How does meiosis allow for variation in offspring?

How does fertilization allow for variation in offspring?

Pedigree and Genes

Now that you know how to breed dragons, let's try some selective breeding in the pedigree view. Use the cross tool to breed a new generation of dragons; breed two of the dragons from this new (F1) generation. Repeat this at least 8 times.

What do you notice about the dragons as you continue to breed more generations?

Use the chromosome tool to closely examine the dragons’ genes. If you had trouble answering the sex-linked question above, now you can observe and compare the X and Y chromosomes

Can you find any genes that are different among the members of your F8 generation?

How many generations do you have to breed until all the dragons are exactly the same?

You are creating an inbred strain of dragons in the final generation(s) of this process. Write a note describing your strain, and explain what is special about all individuals in an inbred strain of organisms.

The Plates Problem

Try breeding some offspring to see results of these crosses. Does the pattern of inheritance of plates tell you anything useful?  

Based on your breeding experiments, where might you expect to find the gene for plates (i.e., On which chromosome might the gene be located?) Why do you think this is correct?

Dragons that grow plates usually do so quite late in their life, so dragons that have a new baby don't know right away whether or not it will grow plates. Which trait(s) exhibited by a baby might help a mother dragon determine whether her baby will grow up to have plates?

Dragon Genes

Genotypes/Phenotypes

Trait

Phenotype

Genotype

Horns

Horns

No Horns

Wings

Wings

No Wings

Legs

4 Legs

2 Legs

No Legs

Tails

Fancy Tail

Plain Tail

Fire-breathing

Fire-breathing Male

Non-fire-breathing Male

Fire-breathing Female

Non-fire-breathing Female

Color

Green Male

Yellow Male

Red Female

Blue Female

Brown Female

Purple Female

Dragon Genes

Genotypes/Phenotypes

Trait

Phenotype

Genotype

Horns

Horns

No Horns

Wings

Wings

No Wings

Legs

4 Legs

2 Legs

No Legs

Tails

Fancy Tail

Plain Tail

Fire-breathing

Fire-breathing Male

Non-fire-breathing Male

Fire-breathing Female

Non-fire-breathing Female

Color

Green Male

Yellow Male

Red Female

Blue Female

Brown Female

Purple Female

Explanation / Answer

Since the question has a lot of sub-parts, I will answer only four of them according to the answering guidelines.

Q. What are the traits exhibited by your dragons? A. The traits exhibited are body colour, fancy tail and wings.

Q. What is the chromosome number (“n”) for the dragons? A. According to the animation it is 3.

Q. Which trait(s) exhibit incomplete dominance? A. Body colour exhibits incomplete dominance

Q. What does it mean for a trait to be incompletely dominant? A. This phenomena incomplete dominance means that the phenotype for the heterozygotes will be intermediate to that of either of the homozygotes. For e.g. in this case the parents had red and yellow coloured body but the child had a green coloured body which was intermediate of both the colours.