Nuclear genome has lost its function as the unique and exclusive determinant of inherited characteristics

Fresh Study minimizes the role of DNA in inheritance


Excerpt: "The development of epigenetic studies in recent years has profoundly enriched our view of genetic inheritance. Most significantly, the nuclear genome has gradually lost its function as the unique and exclusive determinant of inherited characteristics due to mounting waves of data revealing the complex epigenetic networks that heritably control genome expression. A comprehensive picture of epigenetic patterns is now emerging where DNA methylation, histone modification, chromatin patterning and RNA-mediated functions play key regulatory roles on a variety of cellular processes and on the programming of early embryonic development.

Growing evidence indicates that epigenetic states can be transmitted to the germline—most significantly via spermatozoa—and then delivered to the offspring at fertilization and inherited by the progeny (extensively reviewed by Lane et al.  and Rando). A fundamental role in this process is played by extracellular vesicles, heterogeneous membrane-coated particles that can transfer RNA, DNA, proteins and lipids between a broad range of cell types and across species. The cargo of extracellular vesicles is predominantly constituted by a wide range of RNAs including regulatory miRNA, tRNA, lncRNA, piRNA and snRNA, which collectively can modulate the expression of an ample spectrum of genes. In the past decade, extracellular vesicles, particularly exosomes, have emerged as crucial vehicles mediating intercellular communication in a variety of physiological and pathological processes. Extracellular vesicle-mediated intercellular trafficking is not restricted to somatic cells, but is also a phenomenon involving germline cells—most significantly, mature spermatozoa. During sperm maturation, the regulatory RNA content is selectively modified by the interaction with epididymosomes, a class of extracellular vesicles released from somatic epididymis that deliver their cargoes to epididymal spermatozoa. Some of these epididymal RNAs are essential for proper embryonic development.
In summary, a growing body of published data now supports the idea that spermatozoa provide an active system of soma-to-germline communication that crosses the Weismann barrier and contributes to epigenetic formatting of progeny development .

Extracellular vesicles are recognized as effective mediators of intercellular communication. They are released from diverse cellular sources and can pass many different RNA molecules, which may vary in response to stressing stimuli and with the health of the donors."

My comment: DNA is just a passive data base and it has no control over cellular processes. Organismal traits and characteristics are inherited mostly by non coding RNA molecules transferred by extracellular vesicles. These discoveries should help researchers solve the problems in missing heritability, for instance. There is no mechanism for evolution because epigenetic modifications never result in any kind of evolution. Don't get lost, my friends.