Complex sentence: Kalmus discovered a mutant allele on an autosomal gene that expressed ebony body color and other selective advantages in a pattern that is autosomal dominant, but also conveyed harsh disadvantages in a pattern that was completely recessive.
Split into simpler sentences: Kalmus discovered a mutant allele on an autosomal gene that expressed ebony body color and other selective advantages in a pattern that was autosomal dominant. The same allele also conveyed harsh disadvantages in a pattern that was completely recessive.