What is tested in a paternity test?

In a paternity test, the genetic material (DNA) of a child and an alleged father are compared to determine whether the alleged father could be the biological father of the child.

During the paternity test, the following aspects of the DNA are typically analyzed:

1. Short Tandem Repeats (STRs): These are specific regions of DNA that contain repeating sequences of nucleotides. The number of repeats can vary from person to person, creating unique patterns. In paternity tests, multiple STR markers spread across different chromosomes are analyzed to determine if the child has inherited specific STR alleles from the alleged father.

2. Single-Nucleotide Polymorphisms (SNPs): SNPs are variations in a single nucleotide within a DNA sequence. These variations can also be used to compare DNA samples and determine genetic relationships.

The paternity test process involves collecting DNA samples, usually from buccal swabs or blood samples, from the child and the alleged father. The DNA is extracted from the samples and then analyzed in a laboratory using techniques like polymerase chain reaction (PCR) and capillary electrophoresis.

By comparing the STR and SNP patterns of the child and alleged father, paternity testing can establish or exclude paternity with a high degree of accuracy. The probability of paternity is calculated based on the genetic similarities and differences observed between the individuals being tested.

It is important to note that paternity testing can also involve other family members, such as the mother, to confirm or exclude familial relationships. Proper sample collection, DNA analysis, and interpretation by trained professionals are crucial for the reliability of paternity testing results.