What is the molecular basis for these effects?

''We found striking evidence for frequent and strong phenotypic changes in daughters that are attributable in a transgenerational genetic manner to the parental Y chromosome''

In addition to phenotype screening, a carefully designed behavioural test strongly suggested that transgenerational rather than social and environmental factors lead to altered behaviour in the daughters from CSS males.

''These results are especially surprising given the relatively small number of genes on the Y chromosome'' Nadeau and his team found themselves asking ''Do other chromosomes lead to transgenerational effects ? Do transgenerational effects occur in humans? What is the molecular basis for these effects?''

If genetic variants act across generations, then traits have a genetic basis, however this study found that certain 'disease genes' can occur in previous generations and not necessarily in the affected individuals. Undeniably these transgenerational effects depend on the interaction between the background and epigenetic factors relating to the Y chromosome. Nadeau and his colleagues state these transgenerational genetic effects contribute to 'missing heritability' which could persist for generations and that these epigenetic effects can most probably be applied to humans. Thus the attributes of an individual today could depend as much on ancestral parental genetics as on the genetic variants that they inherited.

The next major step in the study of transgenerational effects is to unfold the sequence of molecular events that initiate these epigenetic changes which occur in one generation yet subsequently lead to phenotypic changes is following generations.

"Transgenerational genetic effects of the paternal Y chromosome on daughters' phenotypes"