Complex sentence: In 1995, studies indicated that Notch1 is involved in the segmentation of somites in mice; specifically, defects in somite morphology were observed in Notch1 mutant mice.
Split into simpler sentences: In 1995, studies indicated that Notch 1 is involved in the segmentation of somites in mice. The defects in somite morphology were observed in Notch1 mutant mice.