Brother – Brother DNA testing (same father)

Principles of testing

To determine older brother and younger brother to have blood relationship or not, the test should be based on the Y chromosome and are inherited from father to son. The Y chromosome is the chromosome that defined men gender rules of people. LOCI will analyzed16 gene locus on the Y chromosome.

If the gene on the Y chromosome of the sons is the same, they may conclude they are siblings, and vice versa.


Genealogical Chart: brother – brother (inherited in the Y chromosome of the father)


DNA testing: Sister – sister (same father)

Principles of testing

XX chromosomes defined Female gender traits. An X chromosome received from the Father, the remaining X chromosome received from the mother, in which the X chromosome from father to daughter is the same.

To conclude the two daughter to be siblings or not, we must analyze and compare X chromosomes of 2 sisters. Loci will be analyzed 12 gene loci of X chromosome of 2 sisters, and then Scientific Council may conclude that they have siblings or not.


Genealogical Chart: Sister – Sister (inherited in the X chromosome of the father)

DNA blood tests: brother (sister) – young (same mother)

Principles of testing

Mitochondrial DNA is the DNA exists outside the cell nucleus, is rare genetic mutations, only inherited in maternal family (grandmother, mother, aunt…), so mother who gave birth to children have the same genome mitochondrial.

Based on this principle to determine that they have the same mother or not, LOCI experts will analyze mitochondrial DNA sequences, and then it can be concluded this phylogenetic relationships.


Genealogical Chart: brother (sister) – young (same mother) – inherited in t Mitochondria


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