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- Breitfeld, Jana, et al.
(author)
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Genetic dissection of serum vaspin highlights its causal role in lipid metabolism
- 2023
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In: Obesity. - 1930-7381. ; 31:11, s. 2862-2874
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Journal article (peer-reviewed)abstract
- Objective: Vaspin (visceral adipose tissue derived serine protease inhibitor, SERPINA12) is associated with obesity-related metabolic traits, but its causative role is still elusive. The role of genetics in serum vaspin variability to establish its causal relationship with metabolically relevant traits was investigated. Methods: A meta-analysis of genome-wide association studies for serum vaspin from six independent cohorts (N = 7446) was conducted. Potential functional variants of vaspin were included in Mendelian randomization (MR) analyses to assess possible causal pathways between vaspin and homeostasis model assessment and lipid traits. To further validate the MR analyses, data from Genotype-Tissue Expression (GTEx) were analyzed, db/db mice were treated with vaspin, and serum lipids were measured. Results: A total of 468 genetic variants represented by five independent variants (rs7141073, rs1956709, rs4905216, rs61978267, rs73338689) within the vaspin locus were associated with serum vaspin (all p < 5×10−8, explained variance 16.8%). MR analyses revealed causal relationships between serum vaspin and triglycerides, low-density lipoprotein, and total cholesterol. Gene expression correlation analyses suggested that genes, highly correlated with vaspin expression in adipose tissue, are enriched in lipid metabolic processes. Finally, in vivo vaspin treatment reduced serum triglycerides in obese db/db mice. Conclusions: The data show that serum vaspin is strongly determined by genetic variants within vaspin, which further highlight vaspin's causal role in lipid metabolism.
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| 3. |
- Le Duc, Diana, et al.
(author)
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Kiwi genome provides insights into evolution of a nocturnal lifestyle
- 2015
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In: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 16
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Journal article (peer-reviewed)abstract
- Background: Kiwi, comprising five species from the genus Apteryx, are endangered, ground-dwelling bird species endemic to New Zealand. They are the smallest and only nocturnal representatives of the ratites. The timing of kiwi adaptation to a nocturnal niche and the genomic innovations, which shaped sensory systems and morphology to allow this adaptation, are not yet fully understood. Results: We sequenced and assembled the brown kiwi genome to 150-fold coverage and annotated the genome using kiwi transcript data and non-redundant protein information from multiple bird species. We identified evolutionary sequence changes that underlie adaptation to nocturnality and estimated the onset time of these adaptations. Several opsin genes involved in color vision are inactivated in the kiwi. We date this inactivation to the Oligocene epoch, likely after the arrival of the ancestor of modern kiwi in New Zealand. Genome comparisons between kiwi and representatives of ratites, Galloanserae, and Neoaves, including nocturnal and song birds, show diversification of kiwi's odorant receptors repertoire, which may reflect an increased reliance on olfaction rather than sight during foraging. Further, there is an enrichment of genes influencing mitochondrial function and energy expenditure among genes that are rapidly evolving specifically on the kiwi branch, which may also be linked to its nocturnal lifestyle. Conclusions: The genomic changes in kiwi vision and olfaction are consistent with changes that are hypothesized to occur during adaptation to nocturnal lifestyle in mammals. The kiwi genome provides a valuable genomic resource for future genome-wide comparative analyses to other extinct and extant diurnal ratites.
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| 4. |
- Stäubert, Claudia, et al.
(author)
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Examining the Dynamic Evolution of G Protein-Coupled Receptors
- 2014
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In: G Protein-Coupled Receptor Genetics. - Totowa, NJ : Humana Press. - 9781627037792 - 9781627037785 ; , s. 23-43
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Book chapter (peer-reviewed)abstract
- The valuable source of large-scale genomic information initiated attempts to identify the origin(s) of G protein-coupled receptors (GPCR), count and categorize those genes, and follow their evolutionary history. Being present in fungi, plants, and unicellular eukaryotes, GPCR must have evolved before the plant-fungi-animal split about 1.5 billion years ago. Phylogenetic analyses revealed several kinds of evolutionary patterns that occurred during GPCR evolution including one-to-one orthologous relationships, species-specific gene expansion, and episodic duplication of the entire GPCR repertoire in certain species lineages. These data document the highly dynamic process of birth and death of GPCR genes since hundreds of millions of years. Genetic drift and selective forces have shaped the individual structure of a given receptor gene but also of the species-specific receptor repertoire - a process that is still ongoing. These processes have left footprints in the genomic sequence that can be detected by bioinformatic methods and may help to interpret receptor function in the light of a given species in its environment. Reasonable intraspecies sequence variability in GPCR is either physiologically tolerated or promotes individual phenotypes and adaptation, but also susceptibilities for diseases. Therefore, the impact of GPCR variants in epistatic networks will be an important task of future GPCR research. The chapter summarizes evolutionary processes working on GPCR genes and sheds light on their consequences at the levels of receptor structure and function.
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| 5. |
- Westbury, Michael V, et al.
(author)
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Ecological Specialization and Evolutionary Reticulation in Extant Hyaenidae
- 2021
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In: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 38:9, s. 3884-3897
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Journal article (peer-reviewed)abstract
- During the Miocene, Hyaenidae was a highly diverse family of Carnivora that has since been severely reduced to four species: the bone-cracking spotted, striped, and brown hyenas, and the specialized insectivorous aardwolf. Previous studies investigated the evolutionary histories of the spotted and brown hyenas, but little is known about the remaining two species. Moreover, the genomic underpinnings of scavenging and insectivory, defining traits of the extant species, remain elusive. Here, we generated an aardwolf genome and analyzed it together with the remaining three species to reveal their evolutionary relationships, genomic underpinnings of their scavenging and insectivorous lifestyles, and their respective genetic diversities and demographic histories. High levels of phylogenetic discordance suggest gene flow between the aardwolf lineage and the ancestral brown/striped hyena lineage. Genes related to immunity and digestion in the bone-cracking hyenas and craniofacial development in the aardwolf showed the strongest signals of selection, suggesting putative key adaptations to carrion and termite feeding, respectively. A family-wide expansion in olfactory receptor genes suggests that an acute sense of smell was a key early adaptation. Finally, we report very low levels of genetic diversity within the brown and striped hyenas despite no signs of inbreeding, putatively linked to their similarly slow decline in effective population size over the last ∼2 million years. High levels of genetic diversity and more stable population sizes through time are seen in the spotted hyena and aardwolf. Taken together, our findings highlight how ecological specialization can impact the evolutionary history, demographics, and adaptive genetic changes of an evolutionary lineage.
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