Blood Factor Frequencies

January 14, 2015

Do Now

A suspect has a genotype IAiDD.

Write down:

• The antigens present & their location in the blood

• The antibodies present & their location in the blood

• Their blood type

• The types of blood that they can receive

• The types of blood to which they can donate

• The predicted ratio of blood types of their children, if they marry an O-

person.

Class vs Individualized

Is there a way make it more individualized?

Is blood type class evidence or individualized? Why?

Case study

• Someone broke into the house of a teenaged girl and raped her. Her injuries caused her to bleed.

• The girl reported the crime as soon as the assailant left. She did not have her glasses on during the attack, and was only able to give a very general description of the assailant.

• The police found a man wandering the neighborhood who matched the general description and had blood on his jeans. The man claimed the stains were from a bloody nose his girlfriend’s daughter had earlier in the day

Case study

• Analysis of the blood stains

Conclusions?

Blood Source ABO PGM EAP Hp

Stains on suspect’s jeans

A

Suspect A

Girlfriend’s daughter

O

Victim A

The blood CANNOT have come from the girlfriend’s daughter, as the man claimed. It is possible that it belongs to the victim or to the man. Not very conclusive.

Case study

• Analysis of the blood stains

Conclusions?

Blood Source ABO PGM EAP Hp

Stains on suspect’s jeans

A 2-1 BA 1

Suspect A 1 A 1

Girlfriend’s daughter

O 1 B 2-1

Victim A 2-1 BA 1

The blood stains match the victim but not the suspect or the suspect’s girlfriend’s daughter.

This is fairly strong evidence, especially when coupled with the fact that only 1 out of 100 people will have this blood factor profile.

How to calculate probability

Turn & Talk

You roll one die and flip a coin.

What is the probability that you roll a 3 and flip a heads?

How to calculate probability

To calculate the probability of multiple independent events, you multiply the probability of each event occurring individually.

Probability of rolling a 3 =

Probability of flipping a heads =

Probability of rolling a 3 and

flipping a head 8 out of 100

Probability of Blood Factors

ABO group

Frequency of subtype

PGM group

Frequency of subtype

EAP group

Frequency of subtype

Hp group Frequency of subtype

A 40% 1- 1.8% A 11.2% 1 16.5%B 10% 1+ 40.7% B 39.5% 2 35.0%O 45% 1+1- 17.1% BA 41.4% 2-1 47.9%AB 5% 2+ 3.1% C 0.2%        2- 0.3% CA 3.2%        2+2- 1.9% CB 4.6%        1+2+ 22.3%            1-2+ 4.7%            1+2- 6.8%            1-2- 1.4%        

How did the forensic investigators determine that the victim’s blood factors only occur in ~1 out of 100 individuals?

By multiplying the probability of each individual factor.

Probability of Blood Factors

ABO group

Frequency of subtype

PGM group

Frequency of subtype

EAP group

Frequency of subtype

Hp group Frequency of subtype

A 40% 1- 1.8% A 11.2% 1 16.5%B 10% 1+ 40.7% B 39.5% 2 35.0%O 45% 1+1- 17.1% BA 41.4% 2-1 47.9%AB 5% 2+ 3.1% C 0.2%        2- 0.3% CA 3.2%        2+2- 1.9% CB 4.6%        1+2+ 22.3%            1-2+ 4.7%            1+2- 6.8%            1-2- 1.4%        

What is the frequency of ABO O, PGM 1+2+, and Hp 2?

0.45 X 0.223 X 0.35 = 0.035 = 3.5% or about 4 people out of 100

Probability of Blood Factors

ABO group

Frequency of subtype

PGM group

Frequency of subtype

EAP group

Frequency of subtype

Hp group Frequency of subtype

A 40% 1- 1.8% A 11.2% 1 16.5%B 10% 1+ 40.7% B 39.5% 2 35.0%O 45% 1+1- 17.1% BA 41.4% 2-1 47.9%AB 5% 2+ 3.1% C 0.2%        2- 0.3% CA 3.2%        2+2- 1.9% CB 4.6%        1+2+ 22.3%            1-2+ 4.7%            1+2- 6.8%            1-2- 1.4%        

What is the frequency of ABO B, PGM 1+1-, EAP CB, and Hp 1?

0.1 X 0.171 X 0.046 X 0.35 = 0.00028 = .028% or about 3 people out of 10,000

Closure

• What was our objectives, and what did we learn?

• What was our learner profile trait and how did we demonstrate it?

• How does what we did today tie to our unit question?

Exit Ticket

ABO group Frequency of subtype

PGM group Frequency of subtype

EAP group Frequency of subtype

Hp group Frequency of subtype

A 40% 1- 1.8% A 11.2% 1 16.5%

B 10% 1+ 40.7% B 39.5% 2 35.0%

O 45% 1+1- 17.1% BA 41.4% 2-1 47.9%

AB 5% 2+ 3.1% C 0.2%    

    2- 0.3% CA 3.2%    

    2+2- 1.9% CB 4.6%    

    1+2+ 22.3%        

    1-2+ 4.7%        

    1+2- 6.8%        

    1-2- 1.4%        

What is the probability (in both % and number out of xx) of the following blood factors?ABO A, PGM 1+2-, EAP CB