The phrase "differ apart" is not correct and is not commonly used in written English.
It seems to be a redundancy, as "differ" already implies a distinction.
Example: "The two theories differ in their approach to the problem."
Alternatives: "differ from" or "set apart."
Oak trees a few feet apart differ in the size and shape of their acorns.
Their patterns show what we would nominally expect: proximal time periods bear the most resemblance while those farther apart differ the most.
Since clusters were defined base on nine dimensions, two varieties close together can be in the same cluster or not (if they differ on dimensions apart from 1 & 2).
Patients did not differ from controls apart from alcohol consumption where patients consumed significantly more than controls (z = −2.62, P <.01).
On Negros, the eastern and western sides of the island, at sites less than 50 km apart, differ strongly in the severity of the wet and dry seasons, and also differ in the exact timing of rainfall [ 34, 41].
Studies comparing methylation of several S100 proteins in a given cell line or tissue clearly show that genes lying only several kilobases apart differ in methylation and expression level (Tulchinsky et al. 1992; Wicki et al. 1997; Elder and Zhao, 2002).
This result is striking given that the study regions were 3000 km apart and differ drastically in macroclimatic properties that were likely to have favored different soil biota.
After months of negotiations, the parties had come closer to agreeing on the amount of compensation for the wounded and for the families of the dead, though the two sides are still some $20m apart and differ on the question of liability.
They are about 5 km apart, and differ somewhat.
