Dragon Genes http://www.concord.org/stem-resources/modern-genetics BLY 121L - Ta

Question

Dragon Genes

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

BLY 121L - Take Home Assignment

Due: Start of class time – Tues Nov 10, 2015

Answers MUST be…

typed (no smaller than 11-point font)

complete sentences (i.e., grammatically correct – AND spell check!)

THIS IS NOT A GROUP EFFORT – NO POINTS WILL BE AWARDED, IF YOUR PAPER IS SIMILAR IN CONTENT AND WORDING TO THAT OF YOUR PEER’S.

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.

Note the genotype and dominant/recessive condition for each trait.

When you reach this section of the exercise, be sure to change the genotype for all traits to complete the chart.

What are the traits exhibited by your dragons?

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

Rules

Dominance and Recessive Traits

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

(2.) Which trait(s) exhibit incomplete dominance?

(3.) What does it mean for a trait to be incompletely dominant?

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

Some Traits are Sex-linked

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

(6.) How do sex-linked traits differ from autosomal traits?

A sex-linked trait is carried on the X chromosome and shows up only in males. An autosomal trait will show up in either sex.

Color and Lethal Combinations

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

(8.) On which chromosome is the lethal combination exhibited? What is the lethal combination?

Meiosis

(9.) What is the phenotype of your new dragon?

(10.) Which traits are inherited from the mother dragon? AND Which traits are inherited from the father dragon?

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

(12.) How does meiosis allow for variation in offspring?

(13.) 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.

(14.) 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…

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

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

(17.) 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

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

(19.) 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?

(20.) 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?

Explanation / Answer

Since this question has a lot of sub-parts I would answer the first four according to the answering guidelines.

1) The n number is 3 as there are three chromosomes having a single allele for a gene.

2) The body colour exhibits incomplete dominance as the body colour in the child is intermediate of both the parents.

3) Incomplete dominance is a phenomena where the heterozygotes for a trait exhibit a phenotype that is intermediate of both the phenotypes of homozygotes (both dominat and recessive)

4) This condition heterozygous recessive may happen when their is a non allelic recombination between genes which are not alleles. Since there are two genes for colour, their might be a possibility for the formation of heterozygous recessive condition if recombination between allele of one gene takes place with the allele of another gene.

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