The root of the asymmetry is a procedure called imprinting in which either the mother's or the father's copy of a particular gene is inactivated.
The system analysed is designed for mammalian imprinting in which X-linked genes typically undergo random X-inactivation and lack Y-linked homologues.
To address these questions, we studied an animal model of object recognition; filial imprinting, in which young birds learn to recognize an audiovisual stimulus [15].
For example, sex differences were reported in an animal model of fetal imprinting in which male offspring developed hypertension, but females were protected (23).
Genomic imprinting, in which the monoallelic expression of certain genes depends on the parent of origin, occurs in both therian mammal lineages.
It contributes to processes such as X-inactivation, in which one copy of the X chromosome is silenced in females, and genomic imprinting, in which the expression of a gene depends upon which parent it was inherited from.
For example, sexual imprinting, in which early exposure to conspecifics influences mate choice later in life [ 40], can cause speciation between populations that have diverged in allopatry and experience reinforcement upon secondary contact [ 41- 43].
The most widely used technique for preparing MIPs is non-covalent imprinting, in which the complex of template and functional monomer is formed in situ by non-covalent interactions.
However, epigenetic regulation of gene expression is not always environment-dependent as for parental imprinting in which parent-of-origin-specific expression of a subset of genes is regulated by epigenetic mechanisms.
To achieve this goal, Zeng et al. initiated a so-called "general strategy for surface imprinting" in which a hydrophilic peptide could be located at the surface of nanoparticles after modification.
