Search results
Results From The WOW.Com Content Network
Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. According to modern evolutionary biology, all living beings could be descendants of a unique ancestor commonly referred to as the last universal common ancestor (LUCA) of all life on Earth .
A most recent common ancestor (MRCA), also known as a last common ancestor (LCA), is the most recent individual from which all organisms of a set are descended. The term is also used in reference to the ancestry of groups of genes ( haplotypes ) rather than organisms.
The last universal common ancestor (LUCA) is the hypothesized common ancestral cell from which the three domains of life, the Bacteria, the Archaea, and the Eukarya originated. The cell had a lipid bilayer ; it possessed the genetic code and ribosomes which translated from DNA or RNA to proteins .
Evidence of common descent can also be found through paleontological studies of speciation within geologic strata. The examples described below represent different modes of speciation and provide strong evidence for common descent. Not all speciation research directly observes divergence from "start-to-finish".
The identical ancestors point for Homo sapiens has been the subject of debate. In 2003 Rohde estimated it to be between 5000 and 15,000 years ago. [2] In 2004, Rohde, Olson and Chang showed through simulations that, given the false assumption of random mate choice without geographic barriers, the Identical Ancestors Point for all humans would be surprisingly recent, on the order of 5,000 ...
The concept of common descent is fundamental to the study of evolution, phylogenetics, and cladistics; for instance, all clades, by definition, are rooted in a common ancestor. See also most recent common ancestor. competitive gametic isolation complex trait See quantitative trait. congruent clines consanguineous
Mitochondrial Eve is the most recent common matrilineal ancestor, not the most recent common ancestor. Since the mtDNA is inherited maternally and recombination is either rare or absent, it is relatively easy to track the ancestry of the lineages back to a MRCA; however, this MRCA is valid only when discussing mitochondrial DNA.
The Y-chromosomal most recent common ancestor is the most recent common ancestor of the Y-chromosomes found in currently living human males.. Due to the definition via the "currently living" population, the identity of a MRCA, and by extension of the human Y-MRCA, is time-dependent (it depends on the moment in time intended by the term "currently").