Evolutionary implications of multiple SINE insertions in an intronic region from diverse mammals

An analysis of the nuclear beta-fibrinogen intron 7 locus from 30 taxa representing 12 placental orders of mammals reveals the enriched occurrences of short interspersed clement (SINE) insertion events. Mammalian-wide interspersed repeats (MIRs) are present at orthologous sites of all examined species except those in the order Rodentia. The higher substitution rate in mouse and a rare MIR deletion from rat account for the absence of MIR in the rodents. A minimum of five lineage-specific SINE sequences are also found to have independently inserted into this intron in Carnivora, Artiodactyla and Lagomorpha. In the case of Carnivora, the unique amplification pattern of order-specific CAN SINE provides important evidence for the "pan-carnivore" hypothesis of this repeat element and reveals that the CAN SINE family may still be active today. Particularly interesting is the finding that all identified lineage-specific SINE elements show a strong tendency to insert within or in very close proximity to the preexisting MIRs for their efficient integrations, suggesting that the MIR clement is a hot spot for successive insertions of other SINEs. The unexpected MIR excision as a result of a random deletion in the rat intron locus and the non-random site targeting detected by this study indicate that SINEs actually have a greater insertional flexibility and regional specificity than had previously been recognized. Implications for SINE sequence evolution upon and following integration, as well as the fascinating interactions between retroposons and the host genomes are discussed.

Phylogenetic studies of pantherine cats (Felidae) based on multiple genes, with novel application of nuclear beta-fibrinogen intron 7 to carnivores

The pantherine lineage of the cat family Felidae (order: Carnivora) includes five big cats of genus Panthera and a great many midsized cats known worldwide. Presumably because of their recent and rapid radiation, the evolutionary relationship among pantherines remains ambiguous. We provide an independent assessment of the evolutionary history of pantherine lineage using two complete mitochondrial (mt) genes (ND2 and ND4) and the nuclear beta-fibrmogen intron 7 gene, whose utility in carnivoran phylogeny was first explored. The available four mt (ND5, cytb, 12S, and 16SrRNA) and two nuclear (IRBP and TTR) sequence loci were also combined to reconstruct phylogeny of 14 closely related cat species. Our analyses of combined mt data (six genes; approximate to 3750 bp) and combined mt and nuclear data (nine genes; approximate to 6500 bp) obtained identical tree topologies, which were well-resolved and strongly supported for almost all nodes. Monophyly of Panthera genus in pantherine lineage was confirmed and interspecific affinities within this genus revealed a novel branching pattern, with P. tigris diverging first in Panthera genus, followed by P. onca, P. leo, and last two sister species P. pardus and P. uncia. In addition, close association of Neofelis nebulosa to Panthera, the phylogenetic redefinition of Otocolobus manil within the domestic cat group, and the relatedness of Acinonyx jubatus and Puma concolor were all important findings in the resulting phylogenies. The potential utilities of nine different genes for phylogenetic resolution of closely related pantherine species were also evaluated, with special interest in that of the novel nuclear beta-fibrinogen intron 7. (c) 2005 Elsevier Inc. All rights reserved.

Phylogeny of the caniform carnivora: evidence from multiple genes

The monophyletic group Caniformia in the order Carnivora currently comprises seven families whose relationships remain contentious. The phylogenetic positions of the two panda species within the Caniformia have also been evolutionary puzzles over the past

Multiple maternal origins of chickens: Out of the Asian jungles

Domestic chickens have long been important to human societies for food, religion, entertainment, and decorative uses, yet the origins and phylogeography of chickens through Eurasia remain uncertain. Here, we assessed their origins and phylogeographic hist

Population phylogenomic analysis of mitochondrial DNA in wild boars and domestic pigs revealed multiple domestication events in East Asia

Background: Previously reported evidence indicates that pigs were independently domesticated in multiple places throughout the world. However, a detailed picture of the origin and dispersal of domestic pigs in East Asia has not yet been reported. Results:

Impedance control is tuned to multiple directions of movement

Humans are able to learn tool-handling tasks, such as carving, demonstrating their competency to make and vary the direction of movements in unstable environments. It has been shown that when a single reaching movement is repeated in unstable dynamics, the central nervous system (CNS) learns an impedance internal model to compensate for the environment instability. However, there is still no explanation for how humans can learn to move in various directions in such environments. In this study, we investigated whether and how humans compensate for instability while learning two different reaching movements simultaneously. Results show that when performing movements in two different directions, separated by a 35° angle, the CNS was able to compensate for the unstable dynamics. After adaptation, the force was found to be similar to the free movement condition, but stiffness increased in the direction of instability, specifically for each direction of movement. Our findings suggest that the CNS either learned an internal model generalizing over different movements, or alternatively that it was able to switch between specific models acquired simultaneously. © 2008 IEEE.