Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 36 for “"cichlid"”.
-
Transcriptional divergence during cichlid embryogenesis
Cichlid fishes have undergone rapid speciation, making them one of the largest vertebrate families and among the most striking examples of adaptive radiation. Cichlid research has largely focused on diverging phenotypes of adults despite many of these variable traits likely being established during …
-
Optimal territory size in the convict cichlid (Cichlasoma nigrofasciatum)
… by measuring the growth rate of convict cichlids (Cichlasoma nigrofasciatum) defending food patches that differed in area by more than an order of magnitude. Groups of five fish competed for a food patch of a given size over a 10-day period. I assumed one large fish would defend the food …
-
Epigenetic variability and inheritance in East African cichlid fishes
The hundreds of cichlid species forming part of the radiation of East African Lakes show a remarkable diversity of phenotypic and ecological adaptation. Despite this, recent studies highlighted that genetic diversity within the radiation is among the lowest ever observed in vertebrates. Such a high …
-
Offspring retrieval behaviors after brood loss in the convict cichlid
… young, including retrieval efforts. Convict cichlids (Amatitlania siquia) are an example of a monogamous biparental fish that show shared parental care of young. In the wild, these cichlids defend nests and search for missing young in response to complete or catastrophic brood loss. This …
-
Genetic structure and inversions in the Lake Malawi cichlid radiation
… This thesis focuses on the adaptive radiation of cichlid fishes in Lake Malawi, one of the most dramatic speciation events known in vertebrates. Following a general introduction, I first characterize a new variant callset of 2,198 Malawi cichlids from ~250 species and provide an overview of the …
-
Towards a Pangenome Perspective on the Lake Malawi Cichlid Radiation
The cichlid fishes in the East African Rift lakes are one of nature’s most spectacular vertebrate radiations and form an excellent system to study the evolutionary process of speciation. Lake Victoria, Malawi and Tanganyika are each home to hundreds of species with a wide spectrum of sizes, …
-
Evolution and Development of Pigmentation Patterns in East African Cichlid fishes
… genetics techniques. Using East African cichlid fishes as a model system, I aim to understand the evolutionary origin and diversification of anal fin egg-spots. Egg-spots are an innovation unique to the haplochromine cichlids; yellow to red annular markings typically on male anal fins, …
-
Genetic variation in fast-evolving East African cichlid fishes: an evolutionary perspective
Cichlid fishes from the East African Rift lakes Victoria, Tanganyika and Malawi represent a preeminent example of replicated and rapid evolutionary radiation. In this single natural system, numerous morphological (eg. jaw and tooth shape, color patterns, visual sensitivity), behavioral (eg. …
-
NUCLEAR PROGESTIN RECEPTOR REGULATES FERTILITY AND SPAWNING IN FEMALE CICHLID ASTATOTILAPIA BURTONI
… well understood. I utilize gene editing in the cichlid fish Astatotilapia burtoni to understand the effects of hormones on its well-documented spawning routine. In female cichlids, prostaglandin F2a (PGF2α) drives spawning behaviors. Sensitivity to PGF2α and expression of its receptor, ptgfr, …
-
Colouration evo-devo: the developmental basis of intra-specific variation in cichlid pigmentation
… a trait exhibiting adaptive variation. Cichlid egg-spots are a well-suited model for investigating the development of diversifying traits. Evolving under sexual selection, egg-spots are dense aggregations of xanthophores and iridophores on haplochromine cichlid anal fins, exhibiting …
-
Patterns and process during the diversification of the cichlid fishes in Lake Malawi, Africa
<p>The 500-1000 cichlid species endemic to Lake Malawi constitute one of the most rapid and extensive radiations of vertebrates ever discovered. The objective of this dissertation was to test the assumptions and predictions of several recently published models of cichlid speciation. First, a novel …
-
A role for environmental epigenetics in the rapid diversification of East African cichlid fishes
… remains unclear. Here, I use East African cichlid fishes—a model system for phenotypic plasticity and rapid evolution—to decipher the role of chromatin regulation in the establishment of phenotypic diversity in novel environments. To illustrate chromatin state dynamics genome-wide, I focus …
-
Variation in neural crest development contributes to phenotypic diversification of East African cichlid fishes
The cichlid fishes comprise the largest extant vertebrate family and are the quintessential example of rapid “explosive” adaptive radiations and phenotypic diversification. Despite low genetic divergence, East African cichlids harbour a spectacular intra- and interspecific morphological diversity. …
-
Population genetics of the cichlid, Cynotilapia afra (Günther 1894), in its native and introduced ranges in Lake Malawi
… with range expansions in the natural world. The cichlid species flock of Lake Malawi consists of an estimated 451-800 species and is a textbook example of explosive speciation that has been studied as a model system of evolution in the past three decades. In addition, fish are of major …
-
The Effect of Gonadotropin Releasing Hormone on Opsin Gene Expression and Spectral Sensitivity in Zebra Cichlid Fish (Metriaclima zebra).
… maintenance of species diversity in Lake Malawi cichlid fishes are greatly dependent on optical communication, which is influenced by environmental, physiological and endocrinological factors. The diversity in spectral sensitivity of cichlids has been partially attributed to differences in opsin …
-
Cloning and characterisation of gonadotropin-releasing hormone (GnRH) receptors in the cichlid (Haplochromis burtoni) and the zebrafish (Danio rerio)
… species of teleost fish, Haplochromis burtoni (cichlid) and Dania rerio (zebrafish). A type I GnRH receptor has previously been shown to exist in the cichlid. In the present study degenerate primers designed to extracellular loop three of the mammalian GnRH receptors were used to identify a …
-
Effects of interspecific competition, salinity, and hurricanes on the success of an invasive fish, the Rio Grande cichlid (Herichthys cyanoguttatus)
The Rio Grande cichlid (Herichthys cyanoguttatus) has been established in the Greater New Orleans Metropolitan Area (GNOMA) for at least 20 years. It is often the most common fish species in urban canals and has also been found in natural waterways outside of the GNOMA. The effects and potential …
-
Genetic basis of adaptive radiation in East African cichlids
<p>East African cichlids are a paramount example of adaptive morphological radiation. The most dramatic difference among species occurs in oral jaw design and correlates with ecological niche partitioning. Convergent evolution of trophic forms between lakes suggests a common mechanism. What …
-
Cichlids as a model for the evolution of visual sensitivity
<p>The cichlid fishes of East Africa are the most ecologically diverse radiation of recent vertebrates. These highly visual fish live in habitats ranging from turbid rivers to clear lakes. They have evolved to exploit an astounding array of foraging strategies. The combination of phenotypic …
Page 1 of 2