New research suggests that the expression of biological traits of parents that is inherited by their children through DNA also depends on the histone protein around which our genetic material is wrapped. The study conducted on yeast provides novel evidence that characteristics can be passed on to children in a DNA-independent mechanism.
Histones are spool-like protein molecules around which DNA is wound so that it can be compactly fitted into cells. Without these proteins, the DNA strands of a single cell would stretch up to 6 feet in length. The bound structure of DNA around histones is called chromatin. Chromatin controls unwinding of DNA from histones during the process of gene expression and replication. Histones can be undergo modifications that in turn results in alteration of chromatin, ending in changes in gene expression.
Image credit: Wikipedia
The histone alteration thus cause changes in expression of inherited characteristics and these modifications are transmitted from parents to children. The study by Robin Allshire and colleagues from the School of Biological Sciences, University of Edinburgh, was carried out by artificially altering histone proteins in yeast. The modification process resulted in changes in gene expression and this was passed on to the next generations of yeast.
The study details available on The University of Edinburgh webpage, also raise further questions whether specific modifications in histones may be linked to appearance of a particular trait or it could be associated certain genetically inherited diseases. It also highlights the possibility of environmental influences such as stress, health or diet on histone modifications which could lead to their alteration that are then passed on to future generations.
The widely theorized idea of epigenesis suggests that environmental conditions inpact gene expression and this influence could be passed on to later generations. Allshire’s research which was published in the Science journal supports the theory and proves that genetic traits can also be epigenetically inherited and are not always dependent on DNA for their expression.