Complex sentence: Research still suggests a close relationship between Kogiidae and sperm whale s using mitochondrial DNA, which supports Kogiidae as part of the sperm whale family, although other phylogenetic research raises further questions over a potential relationship between kogiids and ziphiidae.
Split into simpler sentences: Research still suggests a close relationship between Kogiidae and sperm whale s using mitochondrial DNA, which supports Kogiidae as part of the sperm whale family. Other phylogenetic research raises further questions over a potential relationship between kogiids and ziphiidae.