Introgression of Alectoris chukar Genes into a Spanish Wild Alectoris rufa Population

Abstract

In order to detect introgression of other Alectoris genus species into wild populations of Spanish Alectoris rufa, we studied a sample of 93 red-legged partridges (supposed to be A. rufa) captured in the island of Majorca. A set of 31 chukar partridges (Alectoris chukar) from Cyprus and 33 red-legged partridges (A. rufa) from one Spanish farm were also studied to provide suitable populations for comparison. Factorial correspondence analysis on microsatellite genotypes supported a clear distinction of birds from Cyprus, whereas partridges from Majorca and the Spanish farm overlapped in a wide area. The existence of A. chukar mitochondrial DNA in 16 individuals from Majorca indicated introgression into their maternal lineage even if their phenotypes were not different from A. rufa. Bayesian inference based on microsatellite analysis indicated a noticeable degree of genetic proximity to A. chukar only for one of these hybrids.

Current status of the Sardinian partridge (Alectoris barbara) assessed by molecular markers

“…This proved to be a wild partridge from Northern Sardinia, showing a limited (10%) trace of A. rufa DNA in its ancestry. This result strikingly differs from those recently reported for other European partridge populations, where human-caused widescale hybridization seemed to be the rule (Negro et al 2001;Baratti et al 2005;Barbanera et al 2005;Barilani et al 2007a, b;Tejedor et al 2007). In addition, the analysis of individuals sampled in four breeding stations showed levels of genetic variation similar to that in the wild population, while no sign of hybridization was found.…”

“…Multilocus genotyping techniques have already shown to be useful tools for assessing levels of genetic variation and population structure (Randi et al 2003;Tejedor et al 2005;Chen et al 2006;Arruga et al 2007), as well as resolving interspecific hybridization processes in Alectoris taxa (Baratti et al 2005;Barilani et al 2007a, b;Tejedor et al 2007). The microsatellite markers used in these studies had been isolated in the chicken (Gallus gallus) and revealed to be polymorphic in species of the genus Alectoris (Baratti et al 2005), as well as in other Galliformes (Baratti et al 2001).…”

Extensive mitochondrial introgression in North American Great Black-backed Gulls (Larus marinus) from the American Herring Gull (Larus smithsonianus) with little nuclear DNA impact

“…Females being the heterogametic sex in birds, Haldane's rule would also predict that mitochondrial haplotypes show patterns of reduced introgression compared with nuclear alleles (Carling and Brumfield, 2008). However, several cases of interspecific gene flow documented in birds depicted the reverse pattern; no nuclear introgression is detected while the maternally transmitted mtDNA exhibits high levels of introgression (Tejedor et al, 2007;Bellemain et al, 2008;Irwin et al, 2009). This is the same pattern we observed between the North American L. marinus and the sympatric L. smithsonianus.…”

Mitochondrial DNA and microsatellite markers evidence a different pattern of hybridization in red-legged partridge (Alectoris rufa) populations from NW Italy

“…Recent molecular studies on nuclear and/or maternal markers show a significant incidence of chukar genes in most of the A. rufa populations investigated so far. Chukar introgression (A. rufa x A. chukar hybridization) was detected in 45 % of wild populations in the Iberian Peninsula (Blanco-Aguiar et al 2008), and in 17.2 % in Majorca Island (Tejedor et al 2007). Introgression of A. chukar nuclear or mitochondrial DNA have been also described in 30 % of A. rufa populations investigated in southern France (Vallance et al 2006), in 28 % of natural red-legged x rock partridge hybrids in the French Alpes-Maritimes (Barilani et al 2007a), and in Corsican A. rufa populations with frequencies up to 67 % (Barbanera et al 2010).…”