DAPI Banding Pattern of Chromosomes in Several Brassicaceae Species

The nuclear DNA content, the proportion of A+T base pairs, the chromosomal positions of 5S and 25S rRNA genes, as well as of DAPI (4',6-diamidino-2-phenylindole) bands are described for seven species belonging to three different sect ions of the genus Lathyrus. These data and chromosome measurements allowed to establish precise idiograms and to discriminate most of the chromosome pairs of the seven species. The karyotypic features correlate well with the phylogenetic distances between these species.Key words: Lathyrus karyotypes, 5S/25S rDNA loci, FISH, DAPI banding pattern, nuclear DNA content.

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Satellite DNA probes of Alstroemeria longistaminea (Alstroemeriaceae) paint the heterochromatin and the B chromosome, reveal a G-like banding pattern, and point to a strong structural karyotype conservation

PROTOPLASMA ◽

10.1007/s00709-021-01681-7 ◽

2021 ◽

Author(s):

Tiago Ribeiro ◽

Magdalena Vaio ◽

Leonardo P. Félix ◽

Marcelo Guerra

Keyword(s):

Banding Pattern ◽

Satellite Dna ◽

B Chromosome ◽

Dna Probes

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Selection on Rapidly Evolving Proteins in the Arabidopsis Genome

Genetics ◽

10.1093/genetics/163.2.723 ◽

2003 ◽

Vol 163 (2) ◽

pp. 723-733 ◽

Cited By ~ 1

Author(s):

Marianne Barrier ◽

Carlos D Bustamante ◽

Jiaye Yu ◽

Michael D Purugganan

Keyword(s):

Expressed Sequence Tag ◽

Amino Acid Replacement ◽

Adaptive Divergence ◽

Coding Region ◽

Protein Coding ◽

Hierarchical Bayesian Analysis ◽

Brassicaceae Species ◽

Replacement Site ◽

Orthologous Loci ◽

Selection Intensities

Abstract Genes that have undergone positive or diversifying selection are likely to be associated with adaptive divergence between species. One indicator of adaptive selection at the molecular level is an excess of amino acid replacement fixed differences per replacement site relative to the number of synonymous fixed differences per synonymous site (ω = Ka/Ks). We used an evolutionary expressed sequence tag (EST) approach to estimate the distribution of ω among 304 orthologous loci between Arabidopsis thaliana and A. lyrata to identify genes potentially involved in the adaptive divergence between these two Brassicaceae species. We find that 14 of 304 genes (∼5%) have an estimated ω > 1 and are candidates for genes with increased selection intensities. Molecular population genetic analyses of 6 of these rapidly evolving protein loci indicate that, despite their high levels of between-species nonsynonymous divergence, these genes do not have elevated levels of intraspecific replacement polymorphisms compared to previously studied genes. A hierarchical Bayesian analysis of protein-coding region evolution within and between species also indicates that the selection intensities of these genes are elevated compared to previously studied A. thaliana nuclear loci.

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