Donnie had been acting strange, or at least stranger than usual. It was common to find him in his lab, his focus on whatever project he was currently working on. However his newest project seemed to involve studying his brothers. One at a time, from head to tail to toe, it had been fine at first, simple check ups, checking reflexes, eyesight, hearing and so on.

Things had started getting strange when he had started asking for blood samples, Leo had been fine with it, though he had been curious about what Donnie wanted the blood for.

"There are some things that I'm curious about, and I want to check it out," was all the genius turtle had said.

Raph had been a little more reluctant about giving his blood, though in the end Donnie had gotten a sample from his as well, and put it with the other two he already had, one from himself, and Leo's. The last member of their family, Michelangelo, was by far the hardest to get into his lab, let alone get a blood sample from.

Eventually Mikey was brought kicking and screaming to Donnie's lab, by none other than Leo.

"No! I don't wanna! Let me go, Leo you traitor! YOu're not my big brother anymore!" Mikey kicked and struggled, though he froze completely when he saw Donnie standing in front of him suddenly, needle in hand.

"Mikey, I just need a blood sample," Donnie said.

"No, don't make me, Donnie please! Just… just wait until I get injured or something please! No needles!" Mikey cried, and Leo had to tighten his hold on the smaller turtle who truly started to freak out when Donnie ignored his pleas and moved to extract the sample from his brother regardless.

Donnie hadn't managed to extract as large a sample as he had from his other brothers, but the purple banded turtle didn't want to drag his baby brother back in here. Mikey hadn't always had a fear of needles, in fact it had become a recent thing over the past six months, ever since the youngest member of the family had decided to stay up late and watch an old horror movie.

The end result had been weeks of nightmares, and more than a few sleepless nights for them as they helped Mikey control his newfound fear.

Donnie made a mental note to apologise to his only baby brother, before he got back to work. He spent time examining each blood sample, comparing it, running one test after another, creating a folder with each one of his brothers unique results.

The results however had been far different than Donnie had expected, and only made him want to know more. So he started with himself, taking pictures, examining his body from top to bottom. The only thing he didn't have was a way to get x rays, not that he needed them, but it would have made his research a lot smoother.

Once he had all the results for himself, he once again called Leo into his lab, and explained what he wanted to do. Gathering items from his shelves and laying them out on his work table, Leo stood back by the door watching his younger brother apprehensively.

"Why don't you tell me what's going on first, Don." Leo said, the purple banded turtle appeared to have not heard him at all, still mumbling to himself as he gathered more items.

"Donnie!" Leo snapped, and that was enough to gain his attention.

Donnie turned around sharply and stared at Leo, his eyes wide, dark circles under them indicating that he had not slept in quite some time, Leo was sure that if he looked around the room he would find Donnie's coffee cup.

"Donnie, what are you doing? What is all this?" Leo asked gesturing to his brother's work table.

"It's for research," Donnie said as if that would be an acceptable answer.

"Are you going to call all of us back in here again? Or is it just me this time?" Leo questioned.

"No, it will be all of you, I've already done these tests on myself, but there's just more that I have to figure out," Donnie said and moved to turn away again. Leo let out a long sigh and walked further into the room grabbed Donnie by the arm and turned him back around.

"Donnie, stop," Leo said, "What is going on?" Leo asked again.

Donnie stared at Leo, his shoulders sagging as he let out a long sigh. Pulling his arm free from Leo's grip, Donnie moved over to his desk where he kept the new stack of folders. "Ever since we found the mutagen, and I started to learn how it works, how it affects the cells in the body, I started wondering how it had worked on us," Donnie said.

Leo said nothing but came over to stand next to Donnie, looking at the folders the purple banded turtle had picked up.

"Right now this is what I found out about us, just from the blood samples, though I have been running tests on myself for months now, after the blood samples though I realised that things about us were very different," Donnie explained.

"Different how?" Leo frowned.

"Sure you want to know?" Donnie asked, when Leo nodded Donnie sat down in his chair, spreading the folders out on the desk and opened each one of them. "The first thing I noticed was that our blood samples are vastly different," Donnie said. "Your DNA is a perfect split between human and turtle, Raph is similar to you, but I will need to do more tests to find out how close you two are physically."

Donnie watched as Leo leaned over the folders and started comparing the information, even though the blue banded turtle didn't really know what he was looking at, or what he was comparing, he still showed an interest in what Donnie was saying. And he put in an effort to try and understand it as well.

"So why does this have you so worked up?" Leo asked.

"Because while yours and Raph's DNA is the same human turtle mix, it's still not the same, meaning genetically, you two are not brothers," Donnie said and Leo now knew why Donnie was so worked up over this.

"We're still brothers," Leo said firmly. "Whatever these tests prove, it doesn't matter if we share the same blood, we're still brothers."

Donnie gave him a small smile, but said nothing more on that subject as he moved on to the next folder. "This one is Mikey's, I think what I found out would explain why he is more flexible than the rest of us, Mikey isn't a perfect fifty fifty split between human and turtle, he somehow has more human DNA than he does turtle, I want to examine him further to find out how this affects him physically, but after the blood sample, I don't know how willing he'd be to even step foot in here again."

"You did scare him quite a bit with that needle," Leo said. "He's hardly come near me since then too, he's been clinging to Raph a lot."

"I really have to talk to him then," Donnie sighed and Leo nodded.

"I've already talked to him, explained that you have your reasons for needing the blood sample, and he understands that much, he just doesn't like it," Leo explained.

"Yeah," Donnie sighed and started closing the folders. "I want to hold off calling him back in here as long as I possibly can, but I've started the files now, I would hate not to finish them, and his mutation is so different than ours."

"What about your folders?" Leo asked and Donnie paused, staring at the folder he had just been about to close. "Are you different, like Mikey?" Leo asked.

"Yes," Donnie confirmed, though he didn't offer any details and Leo frowned, reaching out he placed a hand on Donnie's.

"What's in your file?"

Donnie took a deep breath and let it out slowly. "I'm the exact opposite as Mikey," Donnie said.

"So… you're more turtle than human?" Leo asked.

"Among other things," Donnie closed the folder. "I won't go into detail about that though, until I can confirm a few things for myself."

Leo nodded. "Alright, just… if you need someone to talk to, I'm here," Leo said. "I don't care what those tests say Don, I'm still going to be your big brother, and I'm still going to look after you." Leo smiled down at Donnie, the purple banded turtle tried to return the smile though it looked a bit forced.

"Thanks, Leo," Donnie said stacking the files up again. "I think, maybe I'm going to go get some rest, if you'd be willing I want to run some more tests tomorrow?"

"I'll do whatever I can to help, but I agree getting some rest might be better at the moment," Leo said. Donnie turned toward his desk, glancing at the papers he still had laying around, lists of tests that he still wanted to run on himself, and on his brothers. But those could wait, he felt drained now, just talking with Leo and explaining the base information that he had discovered so far.

Leo watched as Donnie pushed himself up from the chair and stumbled his way out of the lab, once the olive green turtle was out of sight, Leo turned his attention back toward the files that Donnie had shown him. "We are brothers," Leo told himself firmly, trying to snuff out that small flare of hope that had been lit in the back of his mind. Hope that his growing feelings for his brothers were not as wrong as he thought they were, he could not give in to that small spark of hope, he could not afford to be distracted.

He would not let this information change how he saw his brothers, no matter what happened, and no matter what else Donnie managed to find with his tests.

END