Complex sentence: This finding is, however, contradicted by a study published by Temple University finding that Polynesians and Micronesians have little genetic relation to Melanesians; instead, they found significant distinctions between groups living within the Melanesian islands.
Split into simpler sentences: This finding is, however, contradicted by a study published by Temple University, which found that Polynesians and Micronesians have little genetic relation to Melanesians. Instead, they found significant distinctions among groups living within the Melanesian islands.