Mind-blow­ing, life-sav­ing re­search

The Covington News - - OPINION - JACKIE CUSH­MAN COLUM­NIST To find out more about Jackie Gin­grich Cush­man, and read fea­tures by other Creators Syn­di­cate writ­ers and car­toon­ists, visit www. creators.com.

My mother’s fa­ther died of can­cer be­fore I was born. My mother was preg­nant with me, but had not told her fa­ther that she was to have a sec­ond child. The story I’ve been told is that they opened him up to re­move the can­cer -- and found it ev­ery­where. They closed him back up and sent him home to die.

Both of my mother’s brothers died of can­cer. All three of th­ese men were heavy smok­ers. One ig­nored the signs of po­ten­tial trou­ble for years, and all three died from can­cer.

My mother was di­ag­nosed with can­cer in 1978 and beat it. She was di­ag­nosed a sec­ond time in 2005, but again beat can­cer. She went to heaven last fall, but not due to can­cer. She was not a smoker -- so what was the cause?

Her sis­ter, my aunt, has never had can­cer. I’ve of­ten won­dered: What ge­netic and life­style fac­tors and other trig­gers can make a dif­fer­ence in the cause of can­cer?

There are some sci­en­tific dis­cov­er­ies so mind­blow­ing that when you first hear about them, you know that they are re­ally, re­ally big. There will be ram­i­fi­ca­tions for decades, even though you don’t know what the ram­i­fi­ca­tions will be.

The grand­ness of the dis­cov­ery cap­tures your imag­i­na­tion and changes your thoughts about re- la­tion­ships and life, even though you don’t quite un­der­stand the de­tails, the un­der­pin­nings of the dis­cov­ery.

Such is the dis­cov­ery noted in a New York Times ar­ti­cle this week, “See­ing X Chro­mo­somes in a New Light,” by Carl Zim­mer.

The last time I dealt with chro­mo­somes was in col­lege biology, when I had the mis­taken be­lief that biology was my fu­ture and my ma­jor. A few chem­istry labs and one his­tol­ogy class later, I knew that my fu­ture was not in biology, but in busi­ness, where get­ting an A did not in­volve don­ning gog­gles and aprons for hours at a time.

As a quick re­view, the fe­male chro­mo­somes are XX and males are XY. Chil­dren re­ceive one of their mother’s X chro­mo­somes and ei­ther the X, or Y chro­mo­some from their fa­ther. The trans­mis­sion of the fa­ther’s chro­mo­some determines whether the child is a male or fe­male. This is not new news, but old.

Fe­males, hav­ing two X chro­mo­somes, shut down one of the chro­mo­somes at a cel­lu­lar level. Which X chro­mo­some is shut down varies by cell. In some, it’s the one passed down by the fa­ther; in oth­ers, it’s the chro­mo­some that is passed down by the mother.

OK -- so sci­en­tists have known about this for over five decades, and it’s just now com­ing to my at­ten­tion -- but why the press now?

A re­cent study pub­lished in “Neu­ron, in­cluded maps of the X-chro­mo­some in­ac­ti­va­tion. “They found a re­mark­able com­plex­ity to the pat­tern in which the chro­mo­somes were switched on and off,” ac­cord­ing to Zim­mer.

Fe­males have two copies of the X chro­mo­some, each of which has dif­fer­ent ver­sions of the genes not found on the other. This al­lows for one or the other to be used in the cell, lead­ing to more ge­netic diver­sity than males. If one of the genes has a weak­ness, the other can be used.

“Fe­males sim­ply have ac­cess to realms of biology that males do not have,” Hunt­ing­ton Wil­lard, the di­rec­tor of Duke Univer­sity’s in­sti­tute of Genome Sciences & Pol­icy, noted.

The re­cent pub­lished re­search led by a Dr. Nathans showed il­lu­mi­nated maps of where dif­fer­ent X-chro­mo­somes were ac­ti­vated in var­i­ous cells within the bod­ies of mice. Nathans “spec­u­lates that us­ing chro­mo­somes from both par­ents is es­pe­cially use­ful in the ner­vous sys­tem. It could cre­ate more ways to process in­for­ma­tion. ‘Diver­sity in the brain is the name of the game.’”

What shuts down the sec­ond X chro­mo­some? It’s a num­ber of mol­e­cules, led by what has been named the Xist.

Dr. Lee, a Howard Hughes Med­i­cal In­sti­tute in­ves­ti­ga­tor at Har­vard Med­i­cal School, has found that when the Xist is in­ac­ti­vated and the sec­ond X chro­mo­some is al­lowed to be ac­tive, it cre­ates ex­tra pro­teins. Th­ese ex­tra pro­teins can drive a cell to grow un­con­trol­lably. This ad­di­tional un­con­trol­lable growth makes can­cer more likely.

Women’s brains are cre­ated dif­fer­ently, on the molec­u­lar, cel­lu­lar level. What does this mean? I’m not sure, but I’m fas­ci­nated. Now that we know Xist ex­ists, maybe we can de­ter­mine how it be­comes in­ac­tive -- and en­sure it re­mains in­ac­tive.

To me, this new re­search is both mind-blow­ing and po­ten­tially life-sav­ing.

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