Complex sentence: The clade is dominated by its subclade E1b1 (E-P2 or E-PN2), which is by far the most frequent clade within haplogroup E. Another subclade of E1b, E1b2 (P75), is much more unusual.
Split into simpler sentences: The clade is dominated by sub-clade E1b1 (E-P2 or E-PN2), is by far the most frequent clade. Another sub-clade, E1b2 (P75), a sub-clade of E1b, is much more unusual.