imprinting-duck follows the first thing it sees.

Here are good explanations:

http://en.wikipedia.org/wiki/Epigenetics
http://en.wikipedia.org/wiki/DNA_methylation
http://en.wikipedia.org/wiki/Genomic_imprinting

And here are imprinting maps:
http://www.mgu.har.mrc.ac.uk/research/i … index.html

One example of mosaics is human females.
Randomly, one of two X/X chromosomes is deactivated {for gene balancing (males have only one X chromosome )}. Because one X comes from mother and one from father, they may have different alleles. Thus, a clone of tissue produced from ancestral cell with, say, father’s deactivated X chromosome will have different genotype than a clone produced from the ancestral cell with deactivated mother’s X chromosome.