Absolutely. In fact, in terms of development he and his brother were polar OPPOSITES.
In high school, Marquis was the No. 1 rated point in the country, a guy every powerhouse school in the country wanted, whereas Jeff was a lower-rated late bloomer that all the big time schools ignored (hence why he ended up at Wake Forest). But in college and the pros they went the completely opposite direction, Marquis seemed to stop improving, whereas Jeff exploded and became a genuine star (and current NBA All Star).
Not sure what that means, but I do think it's kinda fascinating how two brothers with virtually the exact same genes, background, size and athleticism levels can follow such completely opposite developmental paths.