@misc{10481/68022,
year = {2021},
month = {3},
url = {http://hdl.handle.net/10481/68022},
abstract = {Background: Eukaryote genomes frequently harbor supernumerary B chromosomes in addition to the “standard” A
chromosome set. B chromosomes are thought to arise as byproducts of genome rearrangements and have mostly
been considered intraspecific oddities. However, their evolutionary transcendence beyond species level has
remained untested.
Results: Here we reveal that the large metacentric B chromosomes reported in several fish species of the genus
Astyanax arose in a common ancestor at least 4 million years ago. We generated transcriptomes of A. scabripinnis
and A. paranae 0B and 1B individuals and used these assemblies as a reference for mapping all gDNA and RNA
libraries to quantify coverage differences between B-lacking and B-carrying genomes. We show that the B
chromosomes of A. scabripinnis and A. paranae share 19 protein-coding genes, of which 14 and 11 were also
present in the B chromosomes of A. bockmanni and A. fasciatus, respectively. Our search for B-specific singlenucleotide
polymorphisms (SNPs) identified the presence of B-derived transcripts in B-carrying ovaries, 80% of
which belonged to nobox, a gene involved in oogenesis regulation. Importantly, the B chromosome nobox paralog
is expressed > 30× more than the A chromosome paralog. This indicates that the normal regulation of this gene is
altered in B-carrying females, which could potentially facilitate B inheritance at higher rates than Mendelian law
prediction.
Conclusions: Taken together, our results demonstrate the long-term survival of B chromosomes despite their lack
of regular pairing and segregation during meiosis and that they can endure episodes of population divergence
leading to species formation.},
organization = {Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)

2014/09634-5
2013/24143-5
2017/22447-8
2018/20610-1
2016/09204-6
2014/26508-3},
organization = {CAPES},
organization = {National Council for Scientific and Technological Development (CNPq)

306054/2006-0},
organization = {Spanish Secretaria de Estado de Investigacion, Desarrollo e Innovacion 

CGL2015-70750-P},
organization = {Junta de Andalucia},
organization = {Sven och Lilly Lawskis fond (Sweden)},
organization = {Marie Sklodowska-Curie Individual Fellowship (European Commission) 

875732},
organization = {Uppsala University},
publisher = {BMC},
keywords = {B chromosomes},
keywords = {Astyanax},
keywords = {Evolution},
keywords = {Genomics},
keywords = {Transcriptomics},
title = {Long-term persistence of supernumerary B chromosomes in multiple species of Astyanax fish},
doi = {10.1186/s12915-021-00991-9},
author = {Silva, Duílio M. Z. de A. and Ruiz-Ruano, Francisco J. and Martín Peciña, María and Martínez Camacho, Juan Pedro},
}