The maintenance of ancient diversity shared among the gene copies in divergent genomes likely points to the ongoing arms-race between the pathogen and the host's immune response.
Although two Branchiostoma group 8-like sequences (Brafl1 and 2) suggest that there has been a duplication event within this lineage, there is no evidence for maintenance of ancient group 8-like gene duplications occurring within the plant, vertebrate, nematode, arthropod, or fungal lineages.
The obvious alternatives to explain high levels of divergence include horizontal gene transfer (HGT) from distantly related species [ 46], maintenance of ancient, trans-specific polymorphism by balancing selection [ 26, 41, 44, 47], re-localization of the gene to the higher mutation rate environment of the nuclear genome [ 48], or relaxed selection in a non-functional pseudogene [ 49].
Unsuccessful in his obstructionism, he went first to Vienna and then to St . Petersburg where, with the connivance of the empress Catherine, he formed the Confederation of Targowica for the maintenance of the ancient institutions of Poland (May 14 , 1792, of which he was the marshal, or dictator, directing its operations from his castle at Tulczyn.
In the studied loggerhead turtle individuals, it results in the maintenance of two ancient allelic lineages.
During the subsequent clonal expansion, variations in environmental selection pressures may have promoted maintenance of the ancient phenotype in certain lineages (which still cause Moko disease) and promoted its loss in others.
In general, the robustly supported observed discordances between gene tree topologies and the species phylogeny can be explained by either HGT of gene clusters or by the independent maintenance of an ancient duplicate gene cluster in specific lineages and its loss in all others.
As a result, the conservation, maintenance and restoration of ancient grasslands are sometimes neglected.
With the advent of street lighting, mains water and sewerage during the Victorian era, maintenance of such an ancient parish with so few parishioners became increasingly uneconomical after the Industrial Revolution.
More than 1,000 people signed the petition, which claimed that not only was Gandhi racist towards black South Africans when he lived in South Africa as a young man, but that he campaigned for the maintenance of India's caste system, an ancient social hierarchy that still defines the status in that country of hundreds of millions of people.
The minting of coins, the establishment of laws governing ancient forests, the maintenance of local roads, the development of cursive script all interest Ackroyd, as do the dining habits of lords and peasants and the travels of the mendicant friars who "turned English preaching into a folk art".
