"Precisely. Mice. The common house mouse. There is also a variety of squirrel that carries 24 chromosomes. The peromyscus and apodemus families of mice—and some other animals, including the rhesus monkey—have 48—cousins whose chromosome doubling eons ago started them up different paths from ours. Mr. Truggles, the ancestor of man was a rodent whose doubled chromosomes gave him new attributes that worked to his evolutionary advantage."
"Is that what is called a mutation?" asked Truggles, interested in spite of himself.
"Mutation? A mutation is a change in one gene. Men mutate every day. How many millions upon millions of years do you think it would take simple mutations to build a man from a rodent—or a lemur, either, for that matter?"
"Well, really, Dr. Allison, I believe you misunderstand what I asked you. Your theory is fine, I'm sure, among scientists, but I'm interested in information about Blan Forsythe."
"That's what I've given you. Blan Forsythe is a tetraploid man. His cells carry 96 chromosomes instead of the normal 48. Every cell of his body is doubled."
"Is that why his skin is liver-colored?" asked Truggles, remembering what Sands had said.
Allison smiled.
"Coincidence," he said. "It's true that liver cells have doubled chromosomes, but that isn't the reason for the color."
"What does all this mean, then?" asked Truggles.
Allison laid his half-smoked cigar carefully on the edge of the ashtray and gazed at Truggles through his spectacles.