Complex sentence: If Sami had carried Haplogroup I in ancient Sami populations; this would imply that any acquired Indo-European maternal admixture with Sami's were relatively small and their lineages; unlike Haplogroup W, could have easily become rare or extinct over time.
Split into simpler sentences: If Sami had carried Haplogroup I in relatively ancient Sami populations; this would imply that any acquired Indo-European maternal admixture with the Sami's were relatively small. And their lineages; unlike Haplogroup W, could have easily become rarer or extinct over time.