Arkhipova Irina R.

No Thumbnail Available
Last Name
Arkhipova
First Name
Irina R.
ORCID
0000-0002-4805-1339

Filters

2005 - 2006 2
2
2
Reset filters

Settings
Subject: Asexual reproduction ×

Search Results

Now showing 1 - 2 of 2
  • Preprint
    Two families of non-LTR retrotransposons, Syrinx and Daphne, from the Darwinulid ostracod, Darwinula stevensoni
    ( 2005-12-15) Schon, Isabelle ; Arkhipova, Irina R.
    Two novel families of non-LTR retrotransposons, named Syrinx and Daphne, were cloned and characterized in a putative ancient asexual ostracod Darwinula stevensoni. Phylogenetic analysis reveals that Daphne is the founding member of a novel clade of non-LTR retroelements, which also contains newly described families from the sea urchin and the silkworm and forms a sister clade to L2-like elements. The Syrinx family of non-LTR retrotransposons exhibits evidence of relatively recent activity, manifested in high levels of sequence similarity between individual copies and a three- to ten-fold excess of synonymous substitutions, which is indicative of purifying selection. The Daphne family may have very few copies with intact open reading frames, and exhibits neutral within-family ratio of non-synonymous to synonymous substitutions. It can additionally be characterized by formation of inverted truncated head-to-head structures. All of these features make recent activity less likely than in the Syrinx family. Our results are discussed in light of the evolutionary consequences of long-term asexuality in general and in Darwinula stevensoni in particular.
  • Preprint
    A deep-branching clade of retrovirus-like retrotransposons in bdelloid rotifers
    ( 2006-09-12) Gladyshev, Eugene A. ; Meselson, Matthew ; Arkhipova, Irina R.
    Rotifers of class Bdelloidea, a group of aquatic invertebrates in which males and meiosis have never been documented, are also unusual in their lack of multicopy LINE-like and gypsy-like retrotransposons, groups inhabiting the genomes of nearly all other metazoans. Bdelloids do contain numerous DNA transposons, both intact and decayed, and domesticated Penelope-like retroelements Athena, concentrated at telomeric regions. Here we describe two LTR retrotransposons, each found at low copy number in a different bdelloid species, which define a clade different from previously known clades of LTR retrotransposons. Like bdelloid DNA transposons and Athena, these elements have been found preferentially in telomeric regions. Unlike bdelloid DNA transposons, many of which are decayed, the newly described elements, named Vesta and Juno, inhabiting the genomes of Philodina roseola and Adineta vaga, respectively, appear to be intact and to represent recent insertions, possibly from an exogenous source. We describe the retrovirus-like structure of the new elements, containing gag, pol, and env-like open reading frames, and discuss their possible origins, transmission, and behavior in bdelloid genomes.