The ost ommon ecent ncestor between two people. For example, for two 1st cousins, their shared grandparent is the MRCA. If the cousins were both boys, they would share their grandfather's Y-chromosome.

Most Recent Common Ancestor (first abbr. I had to look up)

Most Recent Common Ancestor. The ancestor shared most recently between two individuals.

The most recent ancestor that two individuals have in common. For example, first cousins share a grandfather, and second cousins share a great-grandfather. When comparing Y chromosome DNA results, the Most Recent Common Ancestor (MCRA) refers to the direct paternal ancestor for each person. When comparing mitochondrial DNA results, the Most Recent Common Ancestor (MCRA) refers to the direct maternal ancestor for each person.

Acronym for ost ecent ommon ncestor.