Sci­ence close to un­cov­er­ing molec­u­lar scars of child abuse

Calgary Herald - - WEEKEND LIFE - TOM KEENAN Tom Keenan is an award-win­ning journalist, pub­lic speaker, pro­fes­sor in the Fac­ulty of En­vi­ron­men­tal De­sign at the Univer­sity of Cal­gary, and au­thor of the best­selling book Tech­nocreep, (­

Events from the U.S. Supreme Court con­fir­ma­tion hear­ings to the rise of the #MeToo move­ment have brought child abuse, both sex­ual and non-sex­ual, out of the shad­ows. Still, decades­old al­le­ga­tions are of­ten dif­fi­cult to prove and may hinge on the mem­o­ries of the peo­ple in­volved. What if there was a phys­i­cal record of abuse stored in the body that could be an­a­lyzed sci­en­tif­i­cally?

New re­search may open the door to just such a tech­nique. Sci­en­tists at Har­vard and the Univer­sity of Bri­tish Columbia have dis­cov­ered sig­nif­i­cant dif­fer­ences in the sperm of men who were and were not vic­tims of child­hood abuse.

Their se­crets are writ­ten as epi­ge­netic mod­i­fi­ca­tions to their genomes. These are bio­chem­i­cal changes, such as the ad­di­tion of a methyl group, that can turn genes on and off, even though they don’t mod­ify the ba­sic DNA struc­ture.

Re­searchers led by An­drea Roberts of Har­vard’s T.H. Chan School of Pub­lic Health com­pared sperm sam­ples from young adult men who re­ported child­hood phys­i­cal and/or sex­ual abuse with those who didn’t. They found eight DNA re­gions that were more than 10 per cent dif­fer­ent, and one re­gion with a 29 per cent dif­fer­ence. The sci­en­tists say it’s too early to say if these epi­ge­netic changes will af­fect the health of the per­son or his off­spring.

In an in­ter­view from Cam­bridge, Mass., Roberts said that, “The big ques­tion is how does child abuse get un­der the skin to af­fect the phys­i­cal and men­tal health, and one of the hy­pothe­ses is that it af­fects these tags that rest on your genes.”

Asked if she thought this tech­nique might have foren­sic uses in the fu­ture, Roberts said, “It’s not im­plau­si­ble, though it would re­quire much big­ger stud­ies.” She notes that the “epi­ge­netic clock” is al­ready used by po­lice to de­ter­mine the ap­prox­i­mate age of the per­son who sup­plied a blood or other tis­sue sam­ple. “We also know that peo­ple who have had trau­matic ex­pe­ri­ences have an older bi­o­log­i­cal age than their chrono­log­i­cal age, so you can sort of see their ag­ing in their tis­sues.”

There’s even a DNAge™ Epi­ge­netic Ag­ing Clock, based on the work of UCLA pro­fes­sor Steve Horvath, and sold com­mer­cially by Zymo Re­search. It was used in Ger­many to test a refugee claimant who said he was un­der the age of 18. Be­cause of a lack of pre­ci­sion with this tech­nique, this ap­pli­ca­tion was highly con­tro­ver­sial.

UBC med­i­cal ge­net­ics pro­fes­sor Michael Ko­bor, se­nior au­thor on the Har­vard/UBC study, is op­ti­mistic that sperm epi­ge­net­ics may some­day wind up in court­rooms or even Se­nate hear­ing rooms. “It’s con­ceiv­able that the cor­re­la­tions we found be­tween methy­la­tion and child abuse might pro­vide a per­cent­age prob­a­bil­ity that abuse had oc­curred,” he says.

One of the big ques­tions aris­ing from this re­search is whether or not these epi­ge­netic changes can be passed on to off­spring. Roberts notes that “when the sperm meets the egg, there is a mas­sive amount of ge­netic reshuf­fling, and most of the methy­la­tion is at least tem­po­rar­ily erased.” How­ever, she cites ev­i­dence show­ing that male mice pass on the epi­ge­netic ef­fects of en­vi­ron­men­tal ex­po­sure to three gen­er­a­tions of their off­spring, so “it’s not crazy to think that might hap­pen in hu­mans.”

In ad­di­tion to le­gal im­pli­ca­tions, epi­ge­net­ics may play a role in de­sign­ing treat­ments and new drugs. Re­searchers at the Univer­sity of Parma and the U.S. Na­tional In­sti­tute on Drug Abuse re­cently pub­lished a pa­per on DNA methy­la­tion and cannabis use disor­der, which is ba­si­cally the mis­use of pot, which causes se­ri­ous dis­tress or im­pair­ment.

These sci­en­tists found “a sig­nif­i­cantly higher level of DNA methy­la­tion in cannabis users com­pared to con­trols in two of the genes tested.”

They go on to sug­gest that “the dif­fer­en­tially methy­lated re­gions may rep­re­sent biomark­ers and/ or po­ten­tial tar­gets for de­signs of phar­ma­co­log­i­cal ther­a­peu­tic agents.”

An­other re­cent study found that ex­ces­sive al­co­hol con­sump­tion ap­pears to speed up the epi­ge­netic ag­ing process. Also, Swedish ado­les­cents who had hy­per­me­thy­la­tion on a par­tic­u­lar gene tended to have more psy­cho­log­i­cal stress and re­ported be­ing bul­lied and de­pressed more than those with­out this epi­ge­netic trait.

The whole field of biomark­ers is ex­plod­ing rapidly, and it’s a good time to think care­fully about the im­pli­ca­tions. The epi­ge­netic en­ter­prise is still in its early days. Sci­en­tists have an im­per­fect un­der­stand­ing of how epi­ge­netic traits af­fect a per­son’s health, and there’s al­ways the prob­lem of fig­ur­ing out what are causes and what are ef­fects.

What we are learn­ing is that the body stores a great deal of in­for­ma­tion and that ma­chine learn­ing tech­niques, which were used in the Har­vard/UBC study, can as­sist in un­rav­el­ling it. It will take a brave ex­pert wit­ness to bring epi­ge­netic ev­i­dence of child­hood abuse into a court of law. But that day is def­i­nitely com­ing, and these new stud­ies bring it closer in a tan­ta­liz­ing way.

New re­search may open the door to sci­ence soon be­ing able to de­tect child­hood abuse in a per­son’s ge­netic makeup.

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