Firefly and Serenity are copyrighted materials of Mutant Enemy, Universal Pictures and Twentieth-Century Fox. This is a fan story intended for entertainment purposes only. No compensation has been received or will be accepted in connection with this work, and no copyright or trademark infringement is intended or should be implied.

A Different Kind of Blue
Prompt: Homo

Simon nodded to himself as he scanned the results on the screen before him. "Yes, the eyes would be homozygous."

"Homo-what?" came the question from behind him. "Doc, you know I ain't sly. Are you sayin' my genes say I am?"

He sighed, not bothering to turn around and look at Jayne. "No. I'm saying that the genes that determine your eye color are the same. Which doesn't surprise me, since they're blue. It takes two recessive genes to create those."

"Oh," he answered. "I guess there is some truth in these DNA profiles you're running on all of us."

"DNA's not a true or false question. It just is, which is why I'm running these profiles." He paused the screen to stretch. "That, and they'll help me identify you when you finally get hurt too badly to recognize you any other way."

"That's a long day coming, Doc. So how come I have the same genes for my eyes? My parents had different colors."

"If you had different genes, you wouldn't have blue eyes. Brown is dominant; it takes precedence over blue. But it's possible for a brown-eyed person to pass a blue-eyed gene if one of their parents had blue eyes."

"Neither my grandpa nor my grandma had them either. My daddy's whole family has brown eyes."

"That's not possible. Brown eyes are dominant."

Jayne slid off the diagnostic table. "I'm just tellin' you what I know, Doc. Guess there must be a kind of blue eyes that's -- what's that word you used? Dominated?"

"Dominant. And there isn't any record of that in medical history. All of the cases where something like that happened turned out to be cases of mistaken parentage --" he stopped suddenly, realizing the significance of what he was saying.

Jayne's eyes narrowed and his tone became belligerent. "You saying my daddy wasn't my daddy?"

Simon sighed and turned around. "I'm saying that nobody's ever seen a dominant case of blue eyes before. I suppose it's theoretically possible."

"Damn right it is," he retorted before he stomped out. Simon closed his eyes briefly, enjoying the quiet before turning back toward the analysis.

"The human genome was mapped in the early 2000s," announced River from behind him. That's two hundred years before we left Earth-that-Was."

"I know," he said.

"So all known variations of genotype and phenotype were identified five hundred years ago. It's highly unlikely that a new type of phenotype would have arisen in such a short evolutionary time period." She paused. "Someone who's homozygous for brown eyes can't have a blue-eyed child."

"I know, River," answered Simon. "But Jayne doesn't want to accept what I see in his DNA, and I don't see any reason to argue with him."

"Why not?" she asked, sitting down where the other man had been seated before. "Who wouldn't want to know the truth about themself?"

He snapped off the viewer and turned around again, admitting he wouldn't have time to finish the analysis right now. "Human beings are more complicated than their DNA. Even if someone else was Jayne's biological father, that man clearly didn't raise him. So it's legitimate to argue that his father came from a family without blue eyes."

"A father's a father," she answered.

"Is he? Then what about ours?"

At that, she fell silent. "I see. Emotional connections take precedence over biological identity. They're the dominant force. In that case, who is our father?"

"I don't know," he said slowly. His eyes lost focus as he stared past her, thinking. It occurred to him that maybe he should be jealous of Jayne. "Maybe we didn't have one at all."