Bone samples

Question 1

What is one way to prepare a bone sample?

Answer 1

freezer milling (cryogenic)

Question 2

Many extraction processes begin with steps aimed at?

Answer 2

removing contamination

Question 3

After decontamination, the hard tissues are incubated in extraction buffer and?

Answer 3

proteinase K

Question 4

What are some decontamination processes for bone samples?

Answer 4

• physically removing the outer bone surface by immersing in a bleach solution
• exposure to UV radiation

Question 5

Why are the bone samples grinded to a powder?

Answer 5

increases the surface area to the various chemicals in DNA extraction to get more DNA

Question 6

What is widely used for extraction of DNA from bone samples?

Answer 6

phenol-chloroform

Question 7

After cleaning the bones with abrasion what is the next step to clean them?

Answer 7

soak in detergent

Question 8

In the ball milling extraction process of bone samples what is used to freeze the sample?

Answer 8

liquid nitrogen

Question 9

What are the two type of DNA recovery is used with bone samples?

Answer 9

1. mortar and pestle
2. cryogenic

Question 10

What are the benefits of the cyrogenic method over the mortar and pestle?

Answer 10

• preservation of DNA integrity
• efficient cell distribution
• reduced contamination
• consistency in particle size

Question 11

What are the advantages of the mortar and pestle method over cyrogenic?

Answer 11

• cost effective
• simple and traditional
• suitable for small samples

Question 12

Why would we want to decalcify bone samples?

Answer 12

• facilitate cell lysis
• prevent DNA degradation
• improve efficiency
• enhance purity
• prevent interference

Question 13

What are the overall steps in recovering DNA from bone samples?

Answer 13

1. sample prep - clean exterior and remove contaminants
2. decalcification using EDTA to remove calcium ions
3. distruption of bone tissue - cryogenic/mortor and pestle
4. cell lysis
5. protein digestion - proteinase K
6. DNA extraction using phenol-chloroform
7. DNA purification
8. quantification using a spectrophotometer or fluorometer
9. quality check - agarose gel or capillary electrophoresis