Question: John William Friso is the most recent common ancestor of what

Context articles: Common descent
Royal descendants of John William Friso
Last universal common ancestor
Dutch monarchs family tree
Brachyopomorpha
John William Friso, Prince of Orange
Mammaliaformes
Norellius
HLA A1-B8 haplotype
Y-chromosomal Adam

Common descent describes how, in evolutionary biology, a group of organisms share a most recent common ancestor.
 There is evidence of common descent that all life on Earth is descended from the last universal common ancestor (LUCA).
 In July 2016, scientists reported identifying a set of 355 genes from the LUCA of all organisms living on Earth.
The royal descendants of John William Friso, Prince of Orange currently occupy all the hereditary European royal thrones, with Friso and his wife, Landgravine Marie Louise of Hesse-Kassel, being the most recent common ancestors of all the European monarchs.
 Due to the intermarriage of the European royal houses, many monarchs are descended from Friso in more than one way.
 Through history, Friso has also been the ancestor of many monarchs whose thrones no longer exist.
The last universal common ancestor (LUCA), also called the last universal ancestor (LUA), cenancestor, or (incorrectly) progenote, is the most recent population of organisms from which all organisms now living on Earth have a common descent.
 LUCA is the most recent common ancestor of all current life on Earth.
 LUCA should not be assumed to be the first living organism on Earth.
 The LUCA is estimated to have lived some 3.5 to 3.8 billion years ago (sometime in the Paleoarchean era).
 The composition of the LUCA is not directly accessible as a fossil, but can be studied by comparing the genomes of its descendents, organisms living today.
 By this means, a 2016 study identified a set of 355 genes inferred to have been present in the LUCA.
The following is a family tree for the Princes of Orange, a line which culminated in the Dutch monarchy with the accession of Prince William VI to the newly created throne of the Netherlands in 1815.
 Dates given are those of birth and death; for Princes of Orange (shown in bold), the intermediate date is the date of accession to the Princedom.
 By virtue of his marriage to Mary II of England, Prince William III, himself a grandson of Charles I of England, became King of England 1689–1702 (jointly with Mary II until her death in 1694) following the overthrow of his uncle and father-in-law James II of England in the Glorious Revolution.
 The family lineage is of note as John William Friso is the most recent common ancestor of all the current monarchs of Europe.
Brachyopomorpha is a clade of stereospondyl temnospondyls within the infraorder Trematosauria.
 It was constructed in 2000 to include "Bothriceps australis" and the superfamily Brachyopoidea.
 It is phylogenetically defined as a stem-based taxon including "Pelorocephalus" and all taxa closer to it than to "Rhytidosteus".
 In contrast, Brachyopoidea is defined as a node-based taxon including "Brachyops" and "Pelorocephalus" and all descendants of their most recent common ancestor.
 Because "Bothriceps" is not thought to be a descendant of that recent common ancestor and would be more basal than it, the genus is placed just outside Brachyopoidea and is considered to be a sister taxon to the clade.
John William Friso, Prince of Orange-Nassau (Dutch: "Johan Willem Friso van Oranje-Nassau" ; 14 August 1687 – 14 July 1711) became the titular Prince of Orange in 1702.
 He was stadtholder of Friesland until his death by drowning in the Hollands Diep in 1711.
 Friso and his wife, Marie Louise, are ancestors of all European monarchs occupying the throne today.
Mammaliaformes ("mammal-shaped") is a clade that contains the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts.
 It is defined as the clade originating from the most recent common ancestor of Morganucodonta and the crown group mammals; the latter is the clade originating with the most recent common ancestor of extant Monotremata, Marsupialia, and Placentalia.
 Besides Morganucodonta and the crown group mammals, Mammaliaformes includes Docodonta and "Hadrocodium" as well as the Triassic "Tikitherium", the earliest known member of the group.
Norellius is an extinct genus of scleroglossan lizard from the Early Cretaceous of Mongolia.
 It is known from a well-preserved skull that was collected by an American Museum of Natural History expedition to Mongolia in 1923 and cataloged as AMNH FR 21444.
 After its initial cataloging, AMNH FR 21444 was not mentioned again in the scientific literature until 2004 when it was recognized as belonging to a potential early relative of modern groups of squamates such as gekkotans, amphisbaenians, dibamids, and snakes. AMNH FR 21444 was more fully described in a 2006 study that used high-resolution computed tomography to examine the skull and its braincase, and was designated to belong to a new genus and species, Norellius nyctisaurops, in 2015.
 The 2006 study incorporated the specimen into a phylogenetic analysis and found it to be a basal member of an evolutionary grouping called Gekkonomorpha, a stem-based taxon that includes living geckos and legless lizards (pygopodids) and all taxa more closely related to them than to any other living lizard.
 "Norellius" lies outside the node-based taxon Gekkota, a more strictly-defined subgroup of Gekkonomorpha that includes geckos, pygopodids, and all descendants of their most recent common ancestor.
 Therefore, while "Norellius" is more closely related to geckos and pygopodids than it is to any other living group of lizards, it branched off before the most recent common ancestor of these two groups.
 Below is a cladogram showing the position of "Norellius" according to this phylogeny:
HLA A1-B8 (Also:"HL A1,8"; "HL A1,A8"; "HLA A1-Cw7-B8"; "HLA A*01-B*08", "HLA A*0101-B*0801", "HLA A*0101-Cw*0701-B*0801"; "HLA A*01:01-C*07:01-B*08:01") is a multigene haplotype that covers the MHC Class I region of the human major histocompatibility complex on chromosome 6.
 A multigene haplotype is set of inherited alleles covering several genes, or gene-alleles; common multigene haplotypes are generally the result of identity by descent from a common ancestor (share a recent common ancestor for that segment of the chromosome).
 Chromosomal recombination fragments multigene haplotypes as the distance to that ancestor increases in number of generations.
In human genetics, the Y-chromosomal most recent common ancestor (Y-MRCA, informally known as Y-chromosomal Adam) is the most recent common ancestor (MRCA) from whom all currently living humans are descended patrilineally.
 The term Y-MRCA reflects the fact that the Y chromosomes of all currently living males are directly derived from the Y chromosome of this remote ancestor.
 The analogous concept of the matrilineal most recent common ancestor is known as "Mitochondrial Eve" (mt-MRCA, named for the matrilineal transmission of mtDNA), the most recent woman from whom all living humans are descended matrilineally.
 As with "Mitochondrial Eve", the title of "Y-chromosomal Adam" is not permanently fixed to a single individual, but can advance over the course of human history as paternal lineages become extinct.