Researchers have already reconstructed fragments of genetic recipes for extinct animals such as the cave bear, the woolly mammoth and most recently, the moa, a giant bird that was at the top of New Zealand’s food chain until 700 years ago, shortly after the arrival of the Maori. Last year, scientists at the Max Planck Institute for Evolutionary Anthropology sequenced the complete mitochondrial genome of a Neanderthal that died 38,000 years ago. The mitochondria are the cell's powerhouses that have their own sets of genes. Those sequences were derived from tissue, bone and feathers that were preserved, but degraded. The technique usually yields only partial sequences. It may only work for samples up to 100,000 years old. After that, time wrecks the DNA beyond use. Scientists have recently devised another way to sequence ancient genomes using only what they know from those animals' living relatives. "Reverse evolution" is a process that has been used for years to work out the evolutionary history of proteins. But in the past year, a similar technique was applied to genomes.