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Abstract Detail



Genetics Section

Reis, Aryane [1], Sousa, Saulo [1], Vale, Aline [1], Campos, Jose [1], Viccini, Lyderson [1].

Lippia alba (Verbenaceae): a new tropical polyploid complex?

The genus Lippia (Verbenaceae) comprises approximately 100 species of herbs, shrubs, and small trees mainly distributed throughout South and Central America. Most Lippia species can be found in Brazil that is one of the hot spots of the genus. Lippia alba is an aromatic shrub widely used in herbal medicine mainly against digestive, respiratory, cardiovascular disturbances and as a sedative. The species shows a wide distribution, extensive morphological plasticity and several chemotypes but few works have been done to understand the base of this large array of phenotypes. The species has been long recognized as diploid with 2n=30 chromosomes. Recently, two chromosome numerical variations have been reported suggesting the occurrence of polyploidy within the species. This study investigates the genome size variation by flow cytometry for 106 accessions collected in 14 Brazilian States. The DNA C-value varied from 1.17 to 3.45pg showing a large variation on genome size. Chromosome counts revealed five different chromosome numbers that were investigated by conventional and molecular cytogenetic techniques. Three of these chromosome numbers have not been reported before. Large variations were observed among the karyotypes including structural chromosome changes. The number of signals revealed by FISH technique (5S and 45S) indicates that those five cytotypes constitute an autopolyploid complex. In addition, high rates of meiotic irregularities mainly observed in cytotypes with higher chromosome number including abnormal chromosome pairing also contribute to support the hypothesis of a new tropical polyploid complex. Financial support: Capes, Fapemig, CNPq (Brazil)

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1 - Universidade Federal de Juiz de Fora, Biology, Laboratory of Genetics, Juiz de Fora, MG, 36036-900, Brazil

Keywords:
Lippia alba
Polyploidy
cytotypes
FISH
Ribosomal genes.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PGN003
Abstract ID:452
Candidate for Awards:None


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