Abstract
One of the important questions in population dynamics and particularly in population genetics is how to gain information about a population’s past, given its present status. Sources, historical in nature such as written records, archeological such as cemeteries, paleontological such as fossils, or even biological such as ancient DNA, are often of assistance. However in many cases, all that is available is a sample from a contemporary population, with information about its demography or genetic make-up. Sometimes, a mathematical model of population growth may be assumed or statistically inferred from paleo-ecology or by other means. Human populations are of major interest, as are populations of endangered species. Other categories of biological genealogies are gaining prominence. Among them are genealogies of cells in cancerous tumors.