Complex sentence: The spotted green pigeon was shown to be closest to the Nicobar pigeon, yet the genetic distance between the two was more than what is seen within other pigeon species, but similar to the distance between different species in the same genus.
Split into simpler sentences: The spotted green pigeon was shown to be closest to the Nicobar pigeon. The genetic distance between the two was more than is seen within other pigeon species, but similar to the distance between different species within the same genus.