Teranesia

She shrugged. ‘Maybe the bird trade wiped them out. The prettiest fetch the highest prices, and they’re also the easiest to catch.’

Prabir wasn’t so sure; fruit pigeons weren’t exactly birds of paradise. Still, times must have been hard after the war, and maybe there’d been enough of a market to make it worth hunting them down.

Grant pulled open a panel on the rack of analytic equipment, and pushed one of the tubes of blood on to a spike. ‘Now we wait.’

Prabir went for a swim in the deserted harbour, staying in the water until it was so dark that he began to wonder what he might be sharing it with. He’d forgotten to bring a towel out with him, so he sat on the deck for a while to avoid dripping all over the cabin. When he walked back in, Grant glanced up from her workbench, taken unaware. He went over to his bunk to put on a T-shirt.

He called out, ‘Any news?’

‘I’ve got all the sequences.’

‘And?’ He approached her. ‘Is it the same species as the one they found in Ambon?’

Grant replied hesitantly, ‘One of our sequences is almost identical to the Ambon data. And all four have the same novel blood proteins as the Ambon bird.’

Prabir cheered. ‘So you were right: you found it in the wild. Congratulations!’ Grant didn’t look particularly pleased, though. He said, ‘What else?’

She glanced down at her notepad. Prabir could see strings of base-pair codes and a cladogram. ‘They also have genetic markers in common with some of the uncamouflaged species we assumed were gone.’

Prabir tried to make sense of this. ‘You mean, they weren’t wiped out, they started breeding with each other?’

‘No, there’s no evidence of that. Each individual specimen we collected shows signs of a distinct recent ancestry. I’m not even sure that they’re not still separate species.’

‘Now I’m confused.’ He laughed. ‘They look identical, they share exotic blood proteins, but you think they have completely different lineages?’

Grant spread her hands on the bench. ‘I can’t be certain, but it looks to me as if they’ve all converged on the same set of traits, within a couple of generations, without interbreeding. Something has given rise to the same genes for the blood proteins and the camouflage, independently, in at least four different species.’

Prabir sat on the stool beside her. ‘Something?’ This was absurd, she had to be mistaken, but he was hardly equipped to tell her where she’d gone wrong in her analysis. ‘What are you suggesting? There’s a retrovirus on the loose that splices a set of fruit pigeon genes into anything it infects – including some genes that happen to be exactly what fruit pigeons need to vanish into the foliage?’

Grant scowled. ‘I haven’t taken leave of my senses completely. And I don’t have viruses on the brain like you do.’

‘OK, I’ll shut up about viruses. But what’s doing it then? Where did these genes come from?’

She stared down at the bench, still angry with him. He was sure she had an answer, though; she just wasn’t willing to commit it to words.

Prabir said gently, ‘I know how important it is for you to be cautious. But I’m not going to leak your theory to Nature, or sell your data to some rival pharmaceuticals company. And if I’m at risk of fathering children with bright-green feathers, don’t you think I deserve to be told?’

He regretted the words as soon as they were out, but Grant’s expression softened. She said, ‘If these pigeons haven’t interbred for hundreds of thousands of years, what do they still have in common?’

Prabir shrugged. ‘They share the same habitat.’

‘And?’

‘I don’t know. I suppose they’d still share most of their genes, dating back to their last common ancestor.’

Grant said, ‘Exactly. But not just working genes: whole stretches of inactive DNA as well. Don’t you see? That has to be the source of all these “innovations” – they’re not innovations at all! You can’t get functional genes appearing out of nowhere in two or three generations. You just can’t! A random sequence of amino acids doesn’t merely form a useless protein, it forms an ill-conditioned one: a molecule that doesn’t even fold predictably into a well-defined shape. These blood proteins are perfectly conditioned: they have conformations with energy troughs as sharp as haemoglobin’s. The same with the pigmentation morphogenesis proteins that produce the camouflage. The odds of that happening by chance – de novo, in the time frame we’re talking about – are nil.

‘Somehow, these birds must have repaired and reactivated genes from an old common ancestor. They’ve reached back into the archives and dusted off blueprints that haven’t been used for a million years.’ She shook her head, smiling slightly, shocked at her own audacity but triumphant too. ‘That’s what I half suspected all along, but this makes the case a whole lot clearer.’