Media Releases

U of T Researchers uncover major source of evolutionary differences among species

December 20, 2012

TORONTO, ON – Uni­ver­si­ty of Toron­to Temer­ty Temer­ty Fac­ul­ty of Med­i­cine researchers have uncov­ered a genet­ic basis for fun­da­men­tal dif­fer­ences between humans and oth­er ver­te­brates that could also help explain why humans are sus­cep­ti­ble to dis­eases not found in oth­er species.

Sci­en­tists have won­dered why ver­te­brate species, which look and behave very dif­fer­ent­ly from one anoth­er, nev­er­the­less share very sim­i­lar reper­toires of genes. For exam­ple, despite obvi­ous phys­i­cal dif­fer­ences, humans and chim­panzees share a near­ly iden­ti­cal set of genes.

The team sequenced and com­pared the com­po­si­tion of hun­dreds of thou­sands of genet­ic mes­sages in equiv­a­lent organs, such as brain, heart and liv­er, from 10 dif­fer­ent ver­te­brate species, rang­ing from human to frog. They found that alter­na­tive splic­ing — a process by which a sin­gle gene can give rise to mul­ti­ple pro­teins — has dra­mat­i­cal­ly changed the struc­ture and com­plex­i­ty of genet­ic mes­sages dur­ing ver­te­brate evo­lu­tion.

The results sug­gest that dif­fer­ences in the ways genet­ic mes­sages are spliced have played a major role in the evo­lu­tion of fun­da­men­tal char­ac­ter­is­tics of species. How­ev­er, the same process that makes species look dif­fer­ent from one anoth­er could also account for dif­fer­ences in their dis­ease sus­cep­ti­bil­i­ty.

“The same genet­ic mech­a­nisms respon­si­ble for a species’ iden­ti­ty could help sci­en­tists under­stand why humans are prone to cer­tain dis­eases such as Alzheimer’s and par­tic­u­lar types of can­cer that are not found in oth­er species,” says Nuno Bar­bosa-Morais, the study’s lead author and a com­pu­ta­tion­al biol­o­gist in U of T Temer­ty Temer­ty Fac­ul­ty of Medicine’s Don­nel­ly Cen­tre for Cel­lu­lar and Bio­mol­e­c­u­lar Research.  “Our research may lead to the design of improved approach­es to study and treat human dis­eases.”

One of the team’s major find­ings is that the alter­na­tive splic­ing process is more com­plex in humans and oth­er pri­mates com­pared to species such as mouse, chick­en and frog.

“Our obser­va­tions pro­vide new insight into the genet­ic basis of com­plex­i­ty of organs such as the human brain,” says Ben­jamin Blencowe, Pro­fes­sor in U of T’s Bant­i­ng and Best Depart­ment of Research and the Depart­ment of Mol­e­c­u­lar Genet­ics, and the study’s senior author.

“The fact that alter­na­tive splic­ing is very dif­fer­ent even between close­ly relat­ed ver­te­brate species could ulti­mate­ly help explain how we are unique.”

The study, “The Evo­lu­tion­ary Land­scape of Alter­na­tive Slic­ing in Ver­te­brate Species”, is pub­lished in the Decem­ber 21 issue of Sci­ence.


For more infor­ma­tion, please con­tact:

Nicole Bod­nar
Media Rela­tions and Com­mu­ni­ca­tions Spe­cial­ist
Temer­ty Temer­ty Fac­ul­ty of Med­i­cine, Uni­ver­si­ty of Toron­to
Office: 416–978-5811