Paternity testing

Paternity testing

Testing genetic markers that are inherited to confirm or refute a biological relationship

Hospitals don’t do paternity testing unless

Licensed by the state as paternity testing facility

Advantages

Phenotypes are reproducible

Gene frequencies are available

Certain DNA polymorphisms have high exclusion power

Different ways to get DNA

Disadvantages

Some testing has low exclusion

Takes long

Some tests are confusing

Method of ID

Conforontation of all parties

ID sheet (name, address, birthday, race, history, signature)

Photos

Fingerprints and heel prints for babies

First order exclusion (direct)

When a marker is detected in the child but is absent in the mother and alleged father

First order exclusion example

Father:AB

Baby: O

Direct exclusions show

Very strong evidence of non paternity

How many molecular alleles are tested

13 (12 polymorphic, 1 amelogenin)

Amelogenin allele

Determines gender

Second order exclusions (indirect)

A single marker is detected in the child, and a different single marker is detected in the alleged father

Second order example

Father: Jk(a=b+)

Baby: Jk(a+b=)

HLA Class 1 located

All nucleated cells, platelets, and dendritic cells

(HLA-A, B, C)

HLA class 2 located

B lymphs, monos, macros, T-cells, activated endothelial cells, skin (langerhans)

(HLA-D)

HLA Class 3 located

Plasma proteins

(Complement C2, C4, B)

Cytokine genes

Plasma proteins

(TNF-alpha/beta)

Most used molecular test

SSP-PCR

HLA antigen inheritance

Co dominant w 2 alleles