Hotz
Fakultäten » Mathematisch-naturwissenschaftliche Fakultät » Evolutionsbiologie und Umweltwissenschaften, Institut für » Ecology & Environment » Dr. Hansjürg Hotz (ausgetreten) » Hotz
Completed research project
| Title / Titel | Testing the Tangled Bank hypotheses for maintenance of sexual recombination | ||||||||
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| Abstract (PDF, 14 KB) | |||||||||
| Summary / Zusammenfassung | The vast majority of eukaryotes reproduce sexually. This poses a central problem in evolutionary biology: a parthenogenetic female passes twice as many of her genes to progeny as a sexually reproducing female. Why are not all organism parthenogenetic? The Tangled Bank models predict short-term fitness advantage of genetic diversity: in a heterogeneous environment, the exploitation of wider niches by sexually generated and thus genetically diverse progeny reduces their competition. We test these hypotheses using the water frog system. Results include: (1) Coexisting hybrid lineages differ significantly in many fitness-related larval life history traits. (2) Mixtures of clones performed significantly better in porportion of tadpoles metamorphosing than single-clone populations. (3) For two hybrid clones out of four tested, genotype combinations with foreign host genomes. (4) Surprisingly, genotypically more variable groups of nonhybrid sibs raised in artificial ponds were inferior in several larval life history traits to genotypically less variable sibships. (5) Hybrid frequency and amount of clonal diversity are not correlated in natural populations. (6) Superior performance of hybrids relative to both parental species in several larval life history traits is in part a spontaneous result of hybridity. Only one experiment showed immediate advantage of genetic diversity through reduction of competition. Other short-term advantages must be sought. |
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| Publications / Publikationen | Hotz, H.; Semlitsch, R.D.; Gutmann, E.; Guex, G.-D. & Beerli, P. (1999): Spontaneous heterosis in larval life-history traits of hemiclonal frog hybrids. Proc. Natl. Acad. Sci. USA 96: 2171-2176.Semlitsch, R.D.; Hoth, H. & Guex, G.-D. (1997): Competition among tadpoles of coexisting hemiclones of hybridogenetic Rana esculenta: support for the Frozen Niche Variation model. Evolution 51: 1249-1261.Semlitsch, R.D.; Schmiedehausen, S.; Hotz, H. & Beerli, P. (1996): Genetic compatibility between sexual and clonal genomes in local populations of the hybridogenetic Rana esculenta complex. Evol. Ecol. 10: 531-543. | ||||||||
| Keywords / Suchbegriffe | amphibian, body size, clonal reproduction, competition, fitness, Frozen Niche Variation, general-purpose genotype, growth, genetic compatibility, heterosis, hybrid, hybridogenesis, interclonal selection, larval period, local adaptation, metamorphosis, Rana esculenta group, sex, sib competition, Tangled Bank | ||||||||
| Project leadership and contacts / Projektleitung und Kontakte |
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| Funding source(s) / Unterstützt durch |
SNF (Personen- und Projektförderung) |
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| Duration of Project / Projektdauer | to Dec 2005 |