Saguaro and other towering cacti have a scrambled history
Biologists continue to debate the genealogy of the cactus family, even differing by a factor of 10 about how many different genera there are. A study based on new genome sequences of four columnar cacti, including saguaro and cardon, illustrates why this is. Because of the long lives of these columnar cacti, ancient genes drop out at random and give the impression of parallel evolution in those species that retain the genes. …read more
