Disclaimer: I do not own the Turtles. The storyline, however, is totally mine.

Don rubbed his eyes and let out a frusturated sigh. He had been running these DNA sequences for hours, and the result was still the same. An impossible result. An improbable result. Yet one that was by all other definitions was correct.

Donatello's head hurt.

A sudden knock on his door brought him out of his musings.

"Don, dinner's ready. It's lasagna night!"

Don suddenly realized that he was starving. He couldn't remember the last time he had eaten.

"Be there in a sec."

He got up and stretched, his muscles complaining from being in one place for too long. Then he looked at his computer, noting that he had at least 10 minutes before his computer finished compiling the data for the latest of his re-trials. Surely it would prove something that the last five experiments hadn't. It had to.

"Don, nice t' see you among the living again." Don was too tired and eyesore to spare more then a look at Raph. He grabbed a plate and loaded it up with Mikey's "Magnificent and Multi-Ingredient-ed Lasagna." Mikey always insisted on having names for his creations. The rest of them always just humored him- no one else could cook as well as Mikey, and the last time someone (Raph) had criticized how Mikey named food, he found himself eating cold, congealed anchovy pizza for a week.

Don started shoveling the hot pasta dish into his mouth as soon as he sat down. He reached to grab a glass of milk, and found that his whole family, including Splinter, was staring at him. He swallowed, then spoke. "What?"

"Dude, I know my M.M.I.L. is good, but it might taste better if you breathed between each mouthful."

"Sorry. I'm in a hurry." He chugged half of the milk, then resumed inhaling the lasagna.

Raph rolled his eyes. "So what you inventin' this time, a better lightbulb?"

"No, I invented that last week." Don said absentmindedly through his mouthful of food.

Splinter shot a look at Raph. "Raphael, please refrain from using sarcasm against your brothers."

Chastised, Raph looked down so that Splinter couldn't see the annoyed look in Raph's eyes. "Sorry sensei."

Don chugged another glass of milk, then leaped up as he heard his computer beep. "Good food Mikey, thanks." Then he rushed off.

Michaelangelo stared after him. "Kinda like watching a car crash in slow-mo, wasn't it? You really wanna stop watching it, but you can't help it…"

"CRAP!" Don's yell reverberated through the lair.

Everyone fell silent. "Guess his experiment didn't work." Said Leo.

Don came storming out of his lab, a stack of paper under his arm. "It's STILL not coming out right- I'm going to April's. I'll be back later."

He grabbed his trench coat and fedora and tore out of the lair, letting the door slam behind him. His family looked at each other with puzzled looks on their faces.

"Well… he seemed a mite preoccupied tonight, didn't he?" Commented Leo.

Raph snorted. "All I can say is that he has GOT to find some better excuses for seeing April." His comment was met with uncomfortable silence.

Mikey bravely broke the silence. "So, who wants seconds?"

"Are you sure? It came out the same?"

April O'Neil ran a hand through her unruly curls and looked away from her microscope. Her lab bench was littered with various scientific papers and paraphernalia, evidence of the experiments the two had been conducting since Donatello had arrived, two hours previously. "Don, we've run it four times. Add them to your other trials and every single one of them is the same."

Don threw up his hands and leaned back in his chair. He tilted his head back and let out a huge breath. "But those results- they're impossible!"

April swiveled in her chair to look at him. "'When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.'"

Don raised an eye-ridge at her. "And you're Sherlock Holmes-ing it because…"

She shrugged. "It fits the situation. One result like this could be a fluke- 10 identical results means that you've got your solution."

Don shook his head. "But…"

"Don, face it. You guys are still brothers, still family. You all may not be related genetically, but that doesn't mean anything. Pets stores don't usually keep families of turtles together, you know."

Don kept staring at the ceiling. April continued, a bit disconcerted by Don's silence.

"And you guys may not have a trace of the mutagen anywhere in your bodies, but I'm sure that there's a logical explanation. Maybe the mutagen was assimilated into your bodies after you guys... changed."

Don laced his fingers behind his head and stared at the ceiling. "No, I've done extensive research on TGRI- there's always a trace left in the host's body after the mutation is complete. It helps the body adjust and cope with the after-effects."

April crossed her arms and swung her chair around to look head on at Donatello. "If that's true, and if none of you four have the mutagen in your bodies, then how were you guys created?"

Dun-dun-dun! This fic was inspired by my Bio class- We did a lab on DNA fingerprinting and it got me thinking.

It's going to be a short fic- I think. I know that this chapter was a bit complicated, but it WILL be explained in the next chapter. Or the one after that.

Thanks for reading!