dealing with bone samples

Question 1

2. pulverisation

Answer 1

• grinding into a powder to increase its surface area for extraction reagents
• releases DNA from the mineral matrix of bone

Question 2

2b. freezer milling

Answer 2

• pre cooled chambers to cryogenic temperatures (to the temp of liquid nitrogen)- prevents heat damage to DNA
• cryogenic grinder = cools and grinds 2 samples simultaneously (100g per chamber) - grind uniformly = better quality
• N (l) preserves integrity

Question 3

2C mortar and pestle

Answer 3

mechanical method - contamination risk due to manual handling
but more cost effective

Question 4

1. decalcification

Answer 4

softens mineralized tissue
by repeated agitation in EDTA
improves DNA yield but time consuming

Question 5

3. extraction

Answer 5

incubates powder in a lysis buffer (contains proteinase K) to digest organic matrix
- then normal extraction process for DNA eg use a silica column, then centrifuge

Question 6

4. Purification

Answer 6

done by washing –> assess purity by running through agarose gel for example

Question 7

what are commingled remains?

Answer 7

mixture of multiple individuals in a single archaeological or forensic context.