The narrative of caesarean birth appears on several occasions in Greek mythology: in the birth of Dionysus is the God of the grape harvest and winemaking and wine; in the birth of Asclepius the God of medicine and healing; and in the birth of Adonis the God of beauty and desire. It is possible, however not obligatory, that it was not solely a fantasy but also reflected a contemporary medical pr...

The mathematical study of genealogies has yielded important insights in population biology, such as the ability to estimate the time to the most recent common ancestor (MRCA) of a sample of genetic sequences or of a group of individuals. Here we introduce a model of cultural genealogies that is a step toward answering similar questions for cultural traits. In our model individuals can inherit f...

An important clue to the evolutionary history of an allele is the structure of the neighboring region of the genome, which we term the genomic background of the allele. Consider two copies of the allele. How similar we expect their genomic background to be is strongly influenced by the age of their most recent common ancestor (MRCA). We apply diffusion theory, first used by Motoo Kimura as a to...

The mutation process is introduced into the colored coalescent theory. The mutation process can be viewed as an independent Poisson process running on the colored genealogical random tree generated by the colored coalescent process, with the edge lengths of the random tree serving as the time scale for the mutation process. Moving backward along the colored genealogical tree, the color of verti...

The genealogies of samples of orthologous regions from multiple species can be classified by their shapes. Using a neutral coalescent model of two species, I give exact probabilities of each of four possible genealogical shapes: reciprocal monophyly, two types of paraphyly, and polyphyly. After the divergence that forms two species, each of which has population size N, polyphyly is the most lik...

"Felix Mitchell is the biggest drug dealer ever here. He made history in Oakland, Calif.," Owen said. "He's a hero..." He is accused of masterminding the distribution of millions of dollars in heroin and ordering the deaths of five rivals during Oakland's 1980 drug war. But to Owen and scores of kids growing up, as Mitchell did, in East Oakland's bleak 69th Avenue housing projects, Felix Mitche...

Context. Despite their profound effect on the universe, the formation of massive stars and stellar clusters remains elusive. Recent advances in observing facilities and computing power have brought us closer to understanding this formation process. In the past decade, compelling evidence has emerged that suggests Infrared Dark Clouds (IRDCs) may be precursors to stellar clusters. However, the u...