What are the two ways to restrict a genome in order to make a library?

which is the best method and why?

how does it work?

8bp restriction enzyme

partial digestion

partial digestion is more useful because it won't cut at every restriction site. in partial digestion we simply limit the amount of enzyme or reaction time. 

Two Options

1) insert in to cosmid or BAC

2)insert into lambda phage

You have colonies of E. coli cells.

Each colony represents one fragment of the genome

What is the result of a genomic library cloned into a bacteriophage (lambda phage)?

A series of plaques

In the center of each plaque is a group of lambda phages that represents one fragment of the genomic library

1. extract mRNA

2. pass mRNA over resin with oligo(dT)

3. mRNA poly A tail sticks to it

4. remove mRNA from resin

5. Add oligo(dT) primer to mRNA poly A tail

6. Add reverse transcriptase which uses the oligo(dT) primer to start polymerizing DNA from the mRNA

7. Add RNase to nick mRNA

8. Add DNA Polymerase I which replaces mRNA with DNA

9. Ligase seals nicks