Research project Could pachytene piRNAs contribute to reproductive isolation among mammals?
Importantly, A-MYB–TCFL5 axis regulates ~100 specialized genes that produce pachytene PIWI-interacting RNAs (piRNAs) that guide PIWI proteins to cleave target transcripts.
Pachytene piRNAs are highly abundant and diverse, comprising >1-million distinct sequences in mammalian testis. Pachytene piRNA genes are not conserved among mammals, even among modern humans. Only two of the mouse pachytene piRNA genes have mutant phenotypes. The exact functions of pachytene piRNAs thus remain mysterious. We hypothesize that piRNA sequence drift shapes the distinct set of piRNA–target pairs in different species. Such pairs thus probe sperm compatibility and promote reproductive isolation among mammals.