The Y-Chromosome test can determine if two brothers or two half-brothers descend from the same paternal line. This can be either if they are from the same father or the from the same grandfather. This test can be preformed even when there’s no DNA sample from the alleged father.
The Y-Chromosome test confirms paternity through a comparison with a grandfather, (half-)brother or uncle (from the father’s side).
Boys come with an X chromosome and a Y chromosome, while girls are equipped with two X chromosomes, where the X chromosome necessarily comes from their mother and the Y chromosome is inherited from their father who himself inherited it from his own father.
Every male child receives the same Y chromosome from his father because there is relatively little chance that there are mutations on this chromosome.
As chromosome remains unchanged from generation to generation, the study of chromosome Y allows to test the paternity of two brothers, even in the absence of their father.
Who needs to participate in a Y chromosome test? 
Each member frmo a single unbroken male line by the birth could participate in the test, for example:
– a grandfather and grandson (if it is the son of a son of that grandfather)
– a nephew and his uncle (the uncle if the father’s brother)
– a great uncle (brother of the paternal grandfather) and grandson (the son must come from a son of the Grandfather).
– two cousins (as long as their fathers are brothers).
Y Chromosome test results and reliability:
The Y chromosome test is 100% reliable. If one of the two brothers does not have the same Y chromosome as the other or as his grandfather, one can conclude that it has no chance to have the same biological father or grandfather.
If the Y chromosome profiles coincide, paternity is 100% confirmed within the male bloodline. This confirms that the child is from the same bloodline as his grandfather or uncle. Beware though, the test can not exclude that another male from the same bloodline is the child’s biological father (like a paternal uncle or a father’s cousin).
Y Chromosome test pricing and delivery:
The results of a DNA test of the Y chromosome are generally available 7 business days after the receipt of the samples at the laboratory. Pricing depends on the laboratory. Please refer to our price comparison chart.