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Why do mitochondria usually pass from mothers to their children?

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Fluorescent confocal image of HeLa cells with green microtubules outlining cell shapes, red mitochondria, and blue nuclei. — mitochondrion Mitochondria (red) are found throughout the cytoplasm of almost all eukaryotic cells (cell nucleus is shown in blue; cytoskeleton is shown in yellow).

Mitochondria are typically inherited from the mother because of the way fertilization occurs in most organisms. During the formation of an embryo, the mother’s egg cell provides the vast majority of the cytoplasm, which contains the mitochondria.1

While sperm cells also contain mitochondria, they generally do not become incorporated into the developing embryo, and any paternal mitochondria that do enter are typically destroyed. Because of this process, known as maternal inheritance, mitochondrial DNA (mtDNA) is passed down through the maternal line. This unique pattern of transmission is a vital tool for scientists studying human evolution and migration, as it allows researchers to trace ancestral lineages across many generations.123