This is your ref/defcoursework assignment for the HCS104 module. It is weighted for 50% of your final module mark and will assess learning outcomes below:

S5 Perform a number of basic laboratory techniques and

S6 Interpret and analyse data related to experimental work

In this report you will write up ageneticsexperiment class using the template provided. The weightings for each part of the assessment are included after each section.Submission is via Sunspace. The deadline for this is Friday 19thAugust at 4pm.

Background

We will study basic principles of Mendelian inheritance with the use of the fruit fly, Drosophila melanogaster [the name means “black-bodied fruit-lover”]. Drosophila was one of the first organisms to be studied genetically: its small size, short life cycle (10 ~14 days at 25oC), high reproductive rate (an adult female can lay 400-500 eggs in 10 days), and ease of culture and genetic manipulation have made it perhaps the best understood animal genetic system. Many different species, and a large number and wide variety of naturally-occurring and artificially-induced genetic variants are available.

We will study genetic inheritance by considering fruit fly genetics at the following loci:

Locus
Phenotype
Genotype
Eye colour

RR

rr
Wing shape

WW

ww

Name:

Student Number:

Date:

Introduction (500 words)

Q1 Describe the difference between a homozygous and heterozygous gene (5%)?

Q2 Explain the difference between a gentotype and a phentotype with specific examples (5%)

Q3 Describe is the difference between a monohybrid and dihybrid cross? (10%)

Methods (25%)

We have predicted that the underlined alleles are dominant and will study F1 hybrids:

Rred eyes
rsepia eyes
&
Wnormal wings
wvestigial wings

Q4 Describe what is meant by an F1 hybrid? (10%)

Complete the punnet square for a monohybrid cross between heterozygous red-eyed flies:

Parents
R
r

R

Genotype

Phenotype
r

Genotype

Phenotype

Q5 What is the expected ratio of phenotypes (5%):

___ red eyes : ___ sepia eyes

Complete the punnet square for a di cross between heterozygous red-eyed normal-winged flies (10%):

Parents
RW
Rw
rW
rw

RW

Genotype

Phenotype
Rw

Genotype

Phenotype
rW

Genotype

Phenotype
rw

Genotype

Phenotype

Q6 What is the expected ratio of phenotypes (10%):

___ red normal : ___ red vestigial : ___ sepia normal : ___ sepia vestigial

In your first experiment you observed 562 red eyed flies, and 209 sepia eyed flies. In your second experiment you observed 441 red eyed normal winged flies, 150 red eyes vestigial winged flies, 142 sepia eyes normal winged flies and 48 sepia eyes vestigial winged flies.

Results (20%)

In your first experiment you observed 562 red eyed flies, and 209 sepia eyed flies. In your second experiment you observed 441 red eyed normal winged flies, 150 red eyes vestigial winged flies, 142 sepia eyes normal winged flies and 48 sepia eyes vestigial winged flies. Present and analyse your data to determine if the predictions were correct using chi-squared analysis. Remember tables must include a title and a legend.

Discussion (500 words)

Q4 Describe the three Laws of Mendelian inheritance (10%)

Q5 Explain what is meant by the genetic terms codominance and polygenic (10%)

References (15%)

Your answers to the questions should contain references. Use the Vancouver referencing style to cite these correctly. Marks will be given for your referencing style and the choice of source (peer reviewed primary literature will score highly