UGR
  |
> >
Evolutionary Genetics Group
(Ref. BIO-165)
19
August
2019
August 2019
<- ->
L M X J V S D
1 2 3 4
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31

News

< BACK TO LIST

  • Thursday 13/01/2011

    Origen único y reciente de los cromosomas B de E. plorans

    MS aceptado en Genetics

    B chromosomes are dispensable chromosomes found in more than 2000 eukaryotic species, usually behaving as genomic parasite ...

MS aceptado en Genetics

B chromosomes are dispensable chromosomes found in more than 2000 eukaryotic species, usually behaving as genomic parasites. Most B chromosomes seem to be made up of the same kind of DNA sequences present in the A-chromosomes. This sequence similarity makes it difficult to obtain specific molecular probes that may permit B-presence diagnosis without cytogenetical analysis. We have developed a Sequence Characterized Amplified Region (SCAR) marker for B chromosomes in the grasshopper Eyprepocnemis plorans, which specifically amplifies a 1510 bp DNA fragment exclusively in B-carrying individuals. Fluorescent in situ hybridization and Fiber FISH analyses showed that this marker is a tandemly repeated DNA sequence closely intermingled with 45S rDNA. PCR reactions showed the presence of SCAR-like sequences in the A chromosomes, but in two separate fragments, supporting the intraspecific origin of B chromosomes in this species. SCAR marker DNA sequence showed to be identical in B chromosome variants from several localities from Spain and Morocco, and it was very similar to those found in B chromosome variants from Greece and Armenia. This strongly suggests that this sequence was already present in the ancestral B chromosome of this species. In addition, the scarce sequence variation observed among several B variants from very distant populations suggests either, a functional constraint or, more likely, a recent and unique origin for B chromosomes in this species.

 

Desarrollado por: