Gambling addiction is the first behavioral disorder included in DSM-V. The reason is that addicts' brain reacts in the same way as alcohol addicts. This prevents other behavioral disorder (Internet, sex) from going into DSM: those addicts do not show the same brain pattern.
They harbor complete copies of their genome within two separate nuclei. The micronucleus (or MIC) gives rise both to future progeny & to the macronucleus (or MAC), wherein the DNA is shredded, rearranged, and amplified, which allows the essential core of the genome to be expressed at high levels.
Distribution of species in rain forest: What causes the pattern? --- competition or historical accident. Debate. Its implication is about restoration ecology.
Recessive genes may be a cause of some forms of autism. Autism has different forms which have different genes as causes. But the way in which genes are not expressed is in common in different forms of autism.