Limits...
Hybrid breakdown in cichlid fish.

Stelkens RB, Schmid C, Seehausen O - PLoS ONE (2015)

Bottom Line: Studies from a wide diversity of taxa have shown a negative relationship between genetic compatibility and the divergence time of hybridizing genomes.We measured the fitness of F2 hybrids of African haplochromine cichlid fish bred from species pairs spanning several thousand to several million years divergence time.The estimated time window for successful production of F2 hybrids resulting from our data is consistent with the estimated divergence time between the multiple ancestral lineages that presumably hybridized in three major adaptive radiations of African cichlids.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute for Evolutionary Biology, Plön, Germany.

ABSTRACT
Studies from a wide diversity of taxa have shown a negative relationship between genetic compatibility and the divergence time of hybridizing genomes. Theory predicts the main breakdown of fitness to happen after the F1 hybrid generation, when heterosis subsides and recessive allelic (Dobzhansky-Muller) incompatibilities are increasingly unmasked. We measured the fitness of F2 hybrids of African haplochromine cichlid fish bred from species pairs spanning several thousand to several million years divergence time. F2 hybrids consistently showed the lowest viability compared to F1 hybrids and non-hybrid crosses (crosses within the grandparental species), in agreement with hybrid breakdown. Especially the short- and long-term survival (2 weeks to 6 months) of F2 hybrids was significantly reduced. Overall, F2 hybrids showed a fitness reduction of 21% compared to F1 hybrids, and a reduction of 43% compared to the grandparental, non-hybrid crosses. We further observed a decrease of F2 hybrid viability with the genetic distance between grandparental lineages, suggesting an important role for negative epistatic interactions in cichlid fish postzygotic isolation. The estimated time window for successful production of F2 hybrids resulting from our data is consistent with the estimated divergence time between the multiple ancestral lineages that presumably hybridized in three major adaptive radiations of African cichlids.

No MeSH data available.


Average inviability of homospecific, F1 and F2 hybrid crosses.Five different measures of post-mating failure rates (in %) in homospecific, F1 and F2 interspecific hybrid crosses. Bars show inviability averaged across replicated F2 families of the same cross type, and then across the different cross types within homospecifics, F1 hybrids and F2 hybrids. Error bars are standard deviations. Numbers under bars represent the number of families entering analysis. Significant pairwise posthoc comparisons (after Bonferroni correction) are indicated by brackets with asterisks.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4440740&req=5

pone.0127207.g001: Average inviability of homospecific, F1 and F2 hybrid crosses.Five different measures of post-mating failure rates (in %) in homospecific, F1 and F2 interspecific hybrid crosses. Bars show inviability averaged across replicated F2 families of the same cross type, and then across the different cross types within homospecifics, F1 hybrids and F2 hybrids. Error bars are standard deviations. Numbers under bars represent the number of families entering analysis. Significant pairwise posthoc comparisons (after Bonferroni correction) are indicated by brackets with asterisks.

Mentions: Homospecific, F1 and F2 hybrid crosses showed significant differences in hatching rate (F2,20 = 5.34, p = 0.015), 14-day survival (F2,20 = 12.02, p = 0.001), 180-day survival (F2,20 = 5.82, p = 0.011) and cumulative fitness (F2,16 = 6.73, p = 0.009). Only fertilization rate was not significantly different between groups (F2,20 = 3.12, p = 0.069). F2 hybrids consistently showed the highest inviability in all components of fitness, except for fertilization rate (Fig 1).


Hybrid breakdown in cichlid fish.

Stelkens RB, Schmid C, Seehausen O - PLoS ONE (2015)

Average inviability of homospecific, F1 and F2 hybrid crosses.Five different measures of post-mating failure rates (in %) in homospecific, F1 and F2 interspecific hybrid crosses. Bars show inviability averaged across replicated F2 families of the same cross type, and then across the different cross types within homospecifics, F1 hybrids and F2 hybrids. Error bars are standard deviations. Numbers under bars represent the number of families entering analysis. Significant pairwise posthoc comparisons (after Bonferroni correction) are indicated by brackets with asterisks.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440740&req=5

pone.0127207.g001: Average inviability of homospecific, F1 and F2 hybrid crosses.Five different measures of post-mating failure rates (in %) in homospecific, F1 and F2 interspecific hybrid crosses. Bars show inviability averaged across replicated F2 families of the same cross type, and then across the different cross types within homospecifics, F1 hybrids and F2 hybrids. Error bars are standard deviations. Numbers under bars represent the number of families entering analysis. Significant pairwise posthoc comparisons (after Bonferroni correction) are indicated by brackets with asterisks.
Mentions: Homospecific, F1 and F2 hybrid crosses showed significant differences in hatching rate (F2,20 = 5.34, p = 0.015), 14-day survival (F2,20 = 12.02, p = 0.001), 180-day survival (F2,20 = 5.82, p = 0.011) and cumulative fitness (F2,16 = 6.73, p = 0.009). Only fertilization rate was not significantly different between groups (F2,20 = 3.12, p = 0.069). F2 hybrids consistently showed the highest inviability in all components of fitness, except for fertilization rate (Fig 1).

Bottom Line: Studies from a wide diversity of taxa have shown a negative relationship between genetic compatibility and the divergence time of hybridizing genomes.We measured the fitness of F2 hybrids of African haplochromine cichlid fish bred from species pairs spanning several thousand to several million years divergence time.The estimated time window for successful production of F2 hybrids resulting from our data is consistent with the estimated divergence time between the multiple ancestral lineages that presumably hybridized in three major adaptive radiations of African cichlids.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute for Evolutionary Biology, Plön, Germany.

ABSTRACT
Studies from a wide diversity of taxa have shown a negative relationship between genetic compatibility and the divergence time of hybridizing genomes. Theory predicts the main breakdown of fitness to happen after the F1 hybrid generation, when heterosis subsides and recessive allelic (Dobzhansky-Muller) incompatibilities are increasingly unmasked. We measured the fitness of F2 hybrids of African haplochromine cichlid fish bred from species pairs spanning several thousand to several million years divergence time. F2 hybrids consistently showed the lowest viability compared to F1 hybrids and non-hybrid crosses (crosses within the grandparental species), in agreement with hybrid breakdown. Especially the short- and long-term survival (2 weeks to 6 months) of F2 hybrids was significantly reduced. Overall, F2 hybrids showed a fitness reduction of 21% compared to F1 hybrids, and a reduction of 43% compared to the grandparental, non-hybrid crosses. We further observed a decrease of F2 hybrid viability with the genetic distance between grandparental lineages, suggesting an important role for negative epistatic interactions in cichlid fish postzygotic isolation. The estimated time window for successful production of F2 hybrids resulting from our data is consistent with the estimated divergence time between the multiple ancestral lineages that presumably hybridized in three major adaptive radiations of African cichlids.

No MeSH data available.