Lecture 11: Human Genome Project

Question 1

Explain the ‘shotgun approach’

Answer 1

1. Cut DNA from many copies of an entire chromosome into overlapping fragments
2. clone the fragments in plasmid or phage vectors
3. sequence each fragment
4. order the sequences into one overall sequence

Question 2

How do you find genes by their function?

Answer 2

isolate the mRNA’s that genes make and sequence them to reveal their intron/exon structure

Question 3

What are open reading frames (ORF)

Answer 3

sequence of codons that do not contain a stop codon

Question 4

what genes can be hard to find ?

Answer 4

1. small genes
2. overlapping genes
3. intron/exon splice sites

Question 5

How do you find genes by homology ?

Answer 5

1. take human and mouse genes
2. look for tracts of sequence that share homology
3. Sequencies in common imply: they are important and have a function

Question 6

Why are homeotic genes key ?

Answer 6

they are good for determining positional identity along the length of an organism