Part 2: Development

Question 1

Define morphogenesis

Answer 1

Process of shape development, one of three main developmental processes along with differentiation and cell growth

Question 2

Development: three main points

Answer 2

1) Cells have different identities at the early stage of development
2) Broad decisions are made early, more specialized later
3) Cell fate is highly regulated in time and space

Question 3

Main difference between forward and reverse genetics

Answer 3

In forward genetics, mutate population and look for phenotypes, whereas in reverse a specific gene is mutated

Question 4

Name 11 steps of forward genetics

Answer 4

1) Choose a specific and recognizable phenotype
2) Mutagenesis (chemical, radiation or insertional)
3) Saturation screen for every gene involved
4) Genetic analysis (recessive/dominant, complementation)
5) Crude map gene location (molecular markers)
6) Phenotypic analysis
7) Epistasis analysis (xy mutant has x phenotype, x is epistatic to y)
8) Positional cloning (sequence DNA)
9) cDNA from mRNA using reverse transcriptase
10) Similarity search (blast)
11) Determine biochemical role of cloned gene, expression pattern and manipulate development

Question 5

Which of the following are general processes important for the development of all multicellular organisms?

1) Growth
2) Differentiation
3) Regulation
4) Movement of cells

Answer 5

Growth, Differentiation, Regulation

Movement of cells does not occur in plants

Question 6

The DAF-2 gene in C. elegans encodes the insulin-like growth factor 1 (IGF-1) receptor. Loss of function mutations in the daf-2 gene in C.elegans lead to a longer lifespan. How do you find out whether this gene is also involved in the regulation of lifespan in mice?

Answer 6

Reverse genetics, already know the gene and want to determine its function

Question 7

What’s the effect of the IGF-1 receptor knockout

mutation on the lifespan of the knockout mice?

Answer 7

Expect it to increase

Question 8

How many individuals must be screened?

Answer 8

10 000’s for effective mutagen and 100 000’s for less effective mutagen

Question 9

Two recessive mutations in Arabidopsis, a and b, result in bigger flowers. When you cross a/a with b/b, you get plants with bigger flowers.

Answer 9

Both mutations are in the same gene, no complementation