Development. Inheriting maternal mtDNA.

Abstract

In almost all eukaryotes, mitochondrial genes are inherited mainly from the maternal parent ( 1 ). The mechanisms by which this occurs, and their evolutionary advantages, have remained largely elusive. Two reports in this issue, by Sato and Sato ( 2 ) on page 1141 and Al Rawi et al. ( 3 ) on page 1144, show that paternal mitochondria are eliminated from the fertilized oocyte ( 2 , 3 ) by autophagy, a degradation process that removes structures that may threaten cell survival ( 4 ).