MICRO-GEOGRAPHICAL GENETIC STRUCTURE OF INIA GEOFFRENSIS IN THE NAPO-CURARAY RIVER BASIN BY MEANS OF CHESSER´SMODELS - Biology, Evolution and Conservation of River Dolphins Within South America and Asia - page 131

Chapter 8
M ICRO -G EOGRAPHICAL G ENETIC S TRUCTURE OF
I NIA G EOFFRENSIS IN THE N APO -C URARAY R IVER
B ASIN BY M EANS OF C HESSER ´S M ODELS
Manuel Ruiz-García 
Laboratorio de Genética de Poblaciones Molecular-Biología Evolutiva. Unidad de
Genética. Departamento de Biología. Facultad de Ciencias. Pontificia Universidad
Javeriana, Bogotá DC. Colombia.
A BSTRACT
Thirty-three pink river dolphins ( Inia geoffrensis ) were caught at eight sampling
places (one beach and seven lagoons; transect length of 280 km) in the Napo and Curaray
rivers at the Peruvian Amazon. Nine microsatellites were applied to analyze the genetic
structure of this species at the micro-geographic level and diverse population genetics
procedures were used to determine if Inia is a solitary or a social reproductive species.
Chesser's social model was used to determine asymptotic values of the F-statistics and
showed that this species is a social reproductive one and the basic genetic lineages could
be composed of: 1- seven reproductive females per lineage in each breeding period, 2-
the number of reproductive males per linage is not important, 3- a reproductive male with
four females, on average, within each lineage, and thus there is polygyny in this dolphin
species, and 4- a probability of 0.30 that females of a same lineage have chosen the same
male for breeding. This is the first work carried out at a micro-geographic level for a river
dolphin species, where the basic social reproductive parameters are revealed.
Keywords: Inia geoffrensis ; micro-genetic structure; social structure; Chesser's models;
DNA microsatellites; Napo and Curaray rivers; Peru.
 [e-mail] , [e-mail].