Patrilineal and Matrilineal MRCA
Mitochondrial DNA (mtDNA) is nearly immune to sexual mixing, unlike the nuclear DNA whose chromosomes are shuffled and recombined in Mendelian inheritance. Mitochondrial DNA, therefore, can be used to trace matrilineal inheritance and to find the Mitochondrial Eve (also known as the African Eve), the most recent common ancestor of all humans via the mitochondrial DNA pathway.
Similarly Y chromosome is present as a single sex chromosome in the male individual and is passed on to male descendants without recombination. It can be used to trace patrilineal inheritance and to find the Y-chromosomal Adam, the most recent common ancestor of all humans via the Y-DNA pathway.
Mitochondrial Eve and Y-chromosomal Adam have been established by researchers using genealogical DNA tests. Mitochondrial Eve is estimated to have lived about 200,000 years ago. Y-chromosomal Adam is estimated to have lived around 142,000 years ago. The MRCA of humans alive today would therefore need to have lived more recently than either.
It is more complicated to infer human ancestry via autosomal chromosomes. Although an autosomal chromosome contains genes that are passed down from parents to children via independent assortment from only one of the two parents, genetic recombination (chromosomal crossover) mixes genes from non-sister chromatids from both parents during meiosis, thus changing the genetic composition of the chromosome.
Read more about this topic: Mcra, MRCA of A Population Identified By A Single Genetic Marker