‘Identical’ twins? Not according to their DNA

And the fitness angle is...

Overweight/obesity studies are sometimes performed comparing identical twins with fraternal twins assuming that identical twins are identical.

The results are suspect.

"Identical twins may not be nearly as identical as once believed.

Research in 2005 found that identical twins differ in how their genes express themselves. Now scientists have learned that all identical twins may actually differ genetically from their partners to some degree...

In the new study, researchers analyzed 19 pairs of identical twins. Although they did possess nearly identical genomes, closer study revealed they often differed in the number of copies of individual gene segments. For instance, one twin might be missing a segment, or possess more copies of that segment than the other twin.

Such variations could explain why one identical twin can suffer from a disorder while the other remains healthy."

For us, the bottom line remains the same.

We rely on the stablest, i.e., best, science necessary to explain fitness matters and make changes to improve life.

Nothing more. Nothing less.

Because nothing else is needed and everything else is worse and less reliable.