Age and biogeography of major clades in sturgeons and paddlefishes (Pisces: Acipenseriformes)

Complete mitochondrial genomes of the critically endangered Ship sturgeon Acipenser nudiventris from two seas

“…Bayesian phylogenetic analysis (without CR) gives single phylogenetic tree with 100% support for all branches (Figure 1). Ship sturgeon clusters with A. ruthenus, as it was shown in Peng et al (2007), but A. nudiventris-A. ruthenus branch is not a sister clade to A. stellatus as it was found previously (Peng et al 2007;Krieger et al 2008), but has a common ancestor with high chromosome number Ponto-Caspian species such as A. gueldenstaedtii and A. baerii.…”

“…Ship sturgeon clusters with A. ruthenus, as it was shown in Peng et al (2007), but A. nudiventris-A. ruthenus branch is not a sister clade to A. stellatus as it was found previously (Peng et al 2007;Krieger et al 2008), but has a common ancestor with high chromosome number Ponto-Caspian species such as A. gueldenstaedtii and A. baerii. High similarity between ship sturgeon mitogenome sequences from two geographically isolated sea basins indicates that Aral and Caspian seas were connected in the recent past.…”

“…Multiple alignment of A. nudiventris sequences with 20 previously published complete mitochondrial genomes (Inoue et al 2003 Arnason et al 2004;Peng et al 2007;Chen et al 2012;Dong et al 2014a,b;Li et al 2014Li et al , 2015Liao et al 2016;Lu et al 2016) is straightforward except CR, which is highly polymorphic and contains multiple 81-82bp repeats. Complete mtDNA sequence of A. sinensis (Genebank accession no.…”

Genomic Organization and Physical Mapping of Tandemly Arranged Repetitive DNAs in Sterlet<b> </b>(<b><i>Acipenser ruthenus</i></b>)

“…The genomes of sturgeons (Acipenseridae) are highly fragmented as a result of several polyploidization events. Their karyotype is composed of approximately 120 chromosomes, is functionally diploid, and represents the ancestral type for the living relict order of ray-finned fishes, Acipenseriformes [Peng et al, 2007]. Thus, sturgeons represent a natural model for investigation of polyploidization phenomena, and species with low ploidy karyotypes may be used as reference in genomic studies, including those concentrating on the evolution of repetitive sequences after whole-genome duplication.…”

Whole Genome Duplications and the Radiation of Vertebrates

“…Many sturgeons have hugely increased their genome sizes and their number of chromosomes as a result of repeated lineage-specific polyploidization events (Gregory, 2005;Peng et al, 2007). It is interesting to note that all of these pre-TSGD actinopterygian lineages show a low level of species diversity, and only about 40 extant species belong to the four most basal actinopterygian lineages ( Figure 1).…”