passages.id: split_8_test_3456_passage
passages.type: progene_text
passages.text: Considering the unique conservation and chromosomal location of the Ant family genes in mammals , the Ant4 gene may have arisen in mammalian ancestors and been conserved in mammals to serve as the sole and essential mitochondrial ADP / ATP carrier during spermatogenesis where the sex chromosome - linked Ant2 gene is inactivated .