Intrapopulation Chromosomal Polymorphism in Mazama gouazoubira (Cetartiodactyla; Cervidae): The Emergence of a New Species?

Mazama gouazoubira is a small deer species widely distributed in South America. Previous studies have shown that this species presents intraspecific chromosomal polymorphisms, which could affect fertility due to the effects of chromosomal rearrangements on gamete formation. Important aspects regarding the karyotype evolution of this species and the genus remain undefined due to the lack of information concerning the causes of this chromosomal variation. Nineteen individuals belonging to the Mazama gouazoubira population located in the Pantanal were cytogenetically evaluated. Among the individuals analyzed, 9 had B chromosomes and 5 carried a heterozygous centric fusion (2n = 69 and FN = 70). In 3 individuals, the fusion occurred between chromosomes X and 16, in 1 individual between chromosomes 7 and 21, and in another individual between chromosomes 4 and 16. These striking polymorphisms could be explained by several hypotheses. One is that the chromosome rearrangements in this species are recent and not fixed in the population yet, and another hypothesis is that they represent a balanced polymorphism and that heterozygotes have an adaptive advantage. On the other hand, these polymorphisms may negatively influence fertility and raise questions about sustainability or reproductive isolation of the population.

Chemopreventive effects of (-)-hinokinin against 1,2-dimethylhydrazine-induced genotoxicity and preneoplastic lesions in rat colon.

(-)-Hinokinin (1) is a dibenzylbutyrolactone lignan obtained by the partial synthesis of (-)-cubebin. This study reports the antigenotoxic and anticarcinogenic potential of 1 by the comet and aberrant crypt focus assays in the peripheral blood and colon of 4-5-week-old Wistar rats, respectively. The rats were exposed to 1,2-dimethylhydrazine (40 mg/kg) and were treated by gavage with doses of 10, 20, and 40 mg/kg of 1. The results showed that the dose of 40 mg/kg was neither genotoxic nor carcinogenic. In the comet assay, all 1 doses displayed antigenotoxic effects. In addition, this compound (20 and 40 mg/kg) exhibited an anticarcinogenic effect in the aberrant crypt focus assay.