Journal of Environmental Biology

Morphological, morphometrical and molecular (CO1 and ITS)

analysis of the rotifer Asplanchna brightwellii  from selected

freshwater bodies in Central Mexico

 

Jorge Jiménez-Contreras¹, S.S.S. Sarma^2*, Elías Piedra-Ibarra³,
Marissa Calderón-Torres⁴ and S. Nandini²

 

¹Posgrado en Ciencias del Mar y Limnología, Universidad Nacional  Autónoma de México, Ciudad Universitaria, Av. Universidad 3000  Coyoacán, Mexico City, 04510, Mexico

²Laboratorio de Zoología Acuática, Edificio Unidad de Morfofisiología, Universidad Nacional Autónoma de México, Campus Iztacala, Av. de los Barrios no. 1, Iztacala, Tlalnepantla, Edo. de México, 54090, Mexico

^ 3Unidad de Biomedicina, Universidad Nacional Autónoma de México Campus Iztacala, Av. de los Barrios no. 1, Iztacala, Tlalnepantla, Edo. de México, 54090, Mexico

 ⁴Unidad de Prototipos, Universidad Nacional Autónoma de México Campus Iztacala, Av. de los Barrios no. 1, Iztacala, Tlalnepantla, Edo. de México, 54090, Mexico

*Corresponding Author email : ssssarma@gmail.com

 

 

 

 

Publication Data

Paper received:

30 August 2012

 

Revised received:

09 January 2013

 

Accepted:

01 February 2013

 

Abstract

We evaluated different strains of the rotifer Asplanchna brightwellii collected from central Mexico using morphology, morphometry and molecular tools (CO1 and ITS). Three distinct clonal populations from each of the 3 regions (Mexico City, State of Mexico and State of Guerrero) were established under laboratory conditions. For a given waterbody, morphometric comparisons within the populations of A. brightwellii showed almost stable measurements of trophi and with no statistically significant differences among them (p>0.05). However, asplanchnid body length and width as well as the cyst diametervaried significantly depending on the waterbody from which A. brightwellii was collected. The smallest adults (about 700 µm) were from Valerio Trujano lake (Guerrero State) samples while the largest were from Xochimilco lake. Similar tendencies were reflected in the diameter of resting eggs. In addition, morphologically the cysts of A. brightwellii from the three waterbodies showed slightly different pattern. The number of globular structures on the surface of cysts was smaller for Valerio Trujano strain, while these were larger and less numerous for both Xochimilco and Zumpango strains. The ITS region tree displayed two groups Xochimilco and Valerio Trujano -Zumpango, this analysis did not reflect the morphological grouping; on the contrary the CO1 gene tree separated the populations according to morphological clusters and location (Xochimilco, Valerio Trujano and Zumpango lakes). When the tree was built using the combination of both ITS and CO1 sequences, the phylogenetic relationships observed on CO1 gene were consistent; but showed differences with the relationships observed on ITS region tree (only two groups).

 

Key words

CO1, Fingerprinting, ITS, Resting eggs, Rotifers, Trophi

 

 

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