Chapter 14: Serology - Forensic Science

Type O blood

Type O blood

No antigens

A antibodies + B antibodies

Type A blood

A antigens

B antibodies

Type B blood

B antigens

A antibodies

Type AB blood

A and B antigens

No antibodies

Genotypes of type A

I^A I^A, or I^A i

Genotypes of type B

I^B I^B, or I^B i

Genotypes of type AB

I^A I^B

Genotypes of type O

ii

Rh factor is represented through presence of the…

D antigen (+ or -)

Agglutination

Clumping of blood when combined with antibodies

O+

What is the most common blood type?

AB-

What is the rarest blood type?

What species the blood is from

What does the precipitin test determine?

The three questions asked by a forensic scientists regarding blood

1. Is it blood?

2. What species does it belong to?

3. Can it be individualized?

The answers to the three questions asked by forensic scientists regarding blood?

1. Phenolphthalein test, Kastle-Meyer test, Luminol, Benzidine, etc

2. Precipitin test

3. Phenolphthalein, Kastle-Meyer

Homozygous

2 of the same alleles

Heterozygous

2 different alleles

Pubic combings, external genital swabs, cervix swabs, rectal swabs, oral swab, urine sample, clothing, etc.

What are different types of rape evidence?

• photograph/sketch everything before collection

• collect clothing, pubic hair, head hair, genital swab, etc. from suspect

• wear latex gloves while handling evidence

Collecting rape evidence

Acid phosphatase

used to locate/characterize semen stains, a color test; purple color indicates the acid phosphate enzyme

p30

a protein present in seminal plasma

What are components of blood that are pertinent to forensic blood investigation  

Red blood cells, plasma (white blood cells, platelets)