Inheritance of a mtDNA-linked trait
Mitochondrial DNA (mtDNA)
is a genome located in the extranuclear mitochondria. mtDNA is inherited
through the maternal egg cytoplasm, with the father's sperm making no
contribution.
All children of the first
affected woman are affected, including sons. However, only female children can pass the
trait on, again to all of
their descendants. MtDNA thus
persists by being passed down the maternal lineage.
Homework:
Write out the genotypes of every individual in the tree.