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B chromosome diversification pattens in Astatotilapia latifasciata: a comparative analysis between b chromosome and a complement

Grant number: 11/23967-9
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): February 01, 2012
Effective date (End): December 31, 2012
Field of knowledge:Biological Sciences - Genetics
Principal Investigator:Diogo Cavalcanti Cabral de Mello
Grantee:Rafael Takahiro Nakajima
Home Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil


The B chromosomes occur in about 15% of eukaryotes species, being primarily composed of repeated DNAs and heterochromatic. Some studies have been performed regarding the anlysis of distribution, frequency, inheritance mechanisms, structure and origin of these chromosomes. On the other hand, deeper analysis related to the diversification patters of DNA sequences present in the B chromosome and shared with the A complement have not been extensively performed. The cichlid fish have been received great scientific interest due some species have passed through an extensive adaptative radiation process. In some species of this group the presence of a B chromosome was described, as observed in Astatotilapia latifasciata (previous refered as Haplochromis obliquidens). The presente project aim to analyse the genomic content, origin and evolution of the B chromosomes, using as model A. latifasciata. In this species, besides the clasic chromosomal analysis, molecular studies related to sequences present in the B chromosmes (shared with the A complemente) will be possible through the use of molecular data and tools, such as microdissection, nucleotide sequencing and genomic analysis using bioinformatics. These analysis integrating the physical mapping and molecular data are promissing in the elucidation of a miriad of questions related to B chromosome diversification mechanisms, enabiling a deeper knowledge concerning the possible biological roles of these elements in eukaryotes.