Project description:The aim of the experiment is to identify genes that are contributing too variation in the intensity of reddish/brown colouration seen in feathers from a wild x domestic advanced intercross line of chickens. RNA was isolated from growing feathers with varying levels of reddish/brown colouration (eg. dark red, red, orange, yellow). The intensity of the colour was measured relative to a true red colour chart and expressed as percentage of the reference colour. A lower colour score indicates a darker red colour(~0,30) and a pure white gives a score of ~0,95. QTL regions for the peak and average colour score measured across the wing were obtained from a mapping population. An eQTL analysis was performed by using the gene expression levels from all genes located within the previously identified QTL confidence intervals. The gene expression values for the genes located within the confidence intervals are available in the data file.
Project description:Birds and other reptiles possess a diversity of feather and scale-like skin appendages. Feathers are commonly assumed to have originated from ancestral scales in theropod dinosaurs. However, most birds also have scaled feet, indicating birds evolved the capacity to grow both ancestral and derived morphologies. This suggests a more complex evolutionary history than a simple linear transition between feathers and scales. We set out to investigate the evolution of feathers via the comparison of transcriptomes assembled from diverse skin appendages in chicken, emu, and alligator. Our data reveal that feathers and the overlapping ‘scutate’ scales of birds share more similar gene expression to each other, and to two types of alligator scales, than they do to the tuberculate ‘reticulate’ scales on bird footpads. Accordingly, we propose a history of skin appendage diversification, in which feathers and bird scutate scales arose from ancestral archosaur body scales, whereas reticulate scales arose earlier in tetrapod evolution. We also show that many “feather-specific genes” are also expressed in alligator scales. In-situ hybridization results in feather buds suggest that these genes represent ancestral scale genes that acquired novel roles in feather morphogenesis and were repressed in bird scales. Our findings suggest that the differential reuse, in feathers, and suppression, in bird scales, of genes ancestrally expressed in archosaur scales has been a key factor in the origin of feathers – and may represent an important mechanism for the origin of evolutionary novelties.
Project description:The genetic and developmental mechanisms that control the decision between scale and feather growth â two profoundly different epidermal appendages, and an important developmental shift in the evolution of birds from their dinosaurian ancestors â remain poorly understood. Domestic pigeons display dramatic variation in foot epidermal appendages within a single species, and classical studies suggest that a small number of genes control much of this variation; thus pigeons provide a tractable model to understand skin appendage specification and variation. Here we show that feathered feet in pigeons are the consequence of a partial transformation of limb-type identity mediated by cis-regulatory changes in the hindlimb-specific transcription factor Pitx1 and forelimb-specific transcription factor Tbx5. We also demonstrate that ectopic hindlimb expression of Tbx5 is associated with the development of foot feathers in domestic chickens, suggesting that similar developmental mechanisms underlie phenotypic convergence in avian lineages that diverged over 100 MYA. These results show how qualitative and quantitative changes in expression of regional patterning genes can generate localized changes in organ fate and morphology, and provide a viable molecular mechanism for the evolution of hindlimb scale and feather distribution in dromaeosaurs. Examination of H3K27ac status in embryonic limb buds from two domestic pigeon breeds, racing homer and Indian fantail
Project description:Domestic rock pigeons (Columba livia) homozygous for either of two “recessive red” mutations, which are partially-overlapping deletions causing downregulation of Sox10, display brilliant red colors instead of blue/black feathers. Sox10 encodes a transcription factor important for melanocyte differentiation and function, but the precise role that it plays in promoting eumelanin over pheomelanin pigment production in pigeons are unknown. In this study, we perform ChIPseq for SOX10, H3K27ac, and H3K27me3 to better understand the genome occupancy of SOX10 in avian melanocytes.
Project description:Domestication has produced faster-growing strains of animals for use in agriculture, but selection has been applied with little knowledge of the underlying genetic changes that arose throughout the process. Mammals and birds have been domesticated for thousands of years whereas fish have been domesticated only recently; therefore, wild progenitor strains remain for comparison. Rainbow trout (Oncorhynchus mykiss) have undergone intensive selection and domesticated strains grow more rapidly than extant wild strains. To assess physiological pathways altered by domestication, whole-genome mRNA expression was measured in brain, muscle and liver of size-matched domestic and wild trout using a 16K (cGRASP) salmonid microarray. A large number of genes differed between strains, ranging from 3% of genes in brain to 9% in muscle. Domestic fish had more down-regulated genes in the brain relative to wild fish, whereas more genes were up-regulated in domestic liver and muscle. Relative to wild fish, there was a down-regulation of cell division and an up-regulation of structural genes in the brain of domestic fish. In liver from domestic fish, there was an up-regulation of genes related to transport with a down-regulation of lipid binding. Analysis of the functional categories for muscle indicated that most pathways, including pathways related to metabolism and catabolism, were up-regulated in domestic fish. Comparison of these results to other genomic studies on transgenic, domestic and wild salmonids suggests that similar physiological pathways are altered systemically to support faster rates of growth, regardless of the underlying genetic alteration that has caused the altered growth.
Project description:Domestication has produced faster-growing strains of animals for use in agriculture, but selection has been applied with little knowledge of the underlying genetic changes that arose throughout the process. Mammals and birds have been domesticated for thousands of years whereas fish have been domesticated only recently; therefore, wild progenitor strains remain for comparison. Rainbow trout (Oncorhynchus mykiss) have undergone intensive selection and domesticated strains grow more rapidly than extant wild strains. To assess physiological pathways altered by domestication, whole-genome mRNA expression was measured in brain, muscle and liver of size-matched domestic and wild trout using a 16K (cGRASP) salmonid microarray. A large number of genes differed between strains, ranging from 3% of genes in brain to 9% in muscle. Domestic fish had more down-regulated genes in the brain relative to wild fish, whereas more genes were up-regulated in domestic liver and muscle. Relative to wild fish, there was a down-regulation of cell division and an up-regulation of structural genes in the brain of domestic fish. In liver from domestic fish, there was an up-regulation of genes related to transport with a down-regulation of lipid binding. Analysis of the functional categories for muscle indicated that most pathways, including pathways related to metabolism and catabolism, were up-regulated in domestic fish. Comparison of these results to other genomic studies on transgenic, domestic and wild salmonids suggests that similar physiological pathways are altered systemically to support faster rates of growth, regardless of the underlying genetic alteration that has caused the altered growth.
Project description:Domestication has produced faster-growing strains of animals for use in agriculture, but selection has been applied with little knowledge of the underlying genetic changes that arose throughout the process. Mammals and birds have been domesticated for thousands of years whereas fish have been domesticated only recently; therefore, wild progenitor strains remain for comparison. Rainbow trout (Oncorhynchus mykiss) have undergone intensive selection and domesticated strains grow more rapidly than extant wild strains. To assess physiological pathways altered by domestication, whole-genome mRNA expression was measured in brain, muscle and liver of size-matched domestic and wild trout using a 16K (cGRASP) salmonid microarray. A large number of genes differed between strains, ranging from 3% of genes in brain to 9% in muscle. Domestic fish had more down-regulated genes in the brain relative to wild fish, whereas more genes were up-regulated in domestic liver and muscle. Relative to wild fish, there was a down-regulation of cell division and an up-regulation of structural genes in the brain of domestic fish. In liver from domestic fish, there was an up-regulation of genes related to transport with a down-regulation of lipid binding. Analysis of the functional categories for muscle indicated that most pathways, including pathways related to metabolism and catabolism, were up-regulated in domestic fish. Comparison of these results to other genomic studies on transgenic, domestic and wild salmonids suggests that similar physiological pathways are altered systemically to support faster rates of growth, regardless of the underlying genetic alteration that has caused the altered growth.
Project description:Domestication has produced faster-growing strains of animals for use in agriculture, but selection has been applied with little knowledge of the underlying genetic changes that arose throughout the process. Mammals and birds have been domesticated for thousands of years whereas fish have been domesticated only recently; therefore, wild progenitor strains remain for comparison. Rainbow trout (Oncorhynchus mykiss) have undergone intensive selection and domesticated strains grow more rapidly than extant wild strains. To assess physiological pathways altered by domestication, whole-genome mRNA expression was measured in brain, muscle and liver of size-matched domestic and wild trout using a 16K (cGRASP) salmonid microarray. A large number of genes differed between strains, ranging from 3% of genes in brain to 9% in muscle. Domestic fish had more down-regulated genes in the brain relative to wild fish, whereas more genes were up-regulated in domestic liver and muscle. Relative to wild fish, there was a down-regulation of cell division and an up-regulation of structural genes in the brain of domestic fish. In liver from domestic fish, there was an up-regulation of genes related to transport with a down-regulation of lipid binding. Analysis of the functional categories for muscle indicated that most pathways, including pathways related to metabolism and catabolism, were up-regulated in domestic fish. Comparison of these results to other genomic studies on transgenic, domestic and wild salmonids suggests that similar physiological pathways are altered systemically to support faster rates of growth, regardless of the underlying genetic alteration that has caused the altered growth. Microarray analyses were performed on six individual fish per group of wild type and domestic rainbow trout hybridized (one slide per individual) against a common wild-type RNA pool.
Project description:Domestication has produced faster-growing strains of animals for use in agriculture, but selection has been applied with little knowledge of the underlying genetic changes that arose throughout the process. Mammals and birds have been domesticated for thousands of years whereas fish have been domesticated only recently; therefore, wild progenitor strains remain for comparison. Rainbow trout (Oncorhynchus mykiss) have undergone intensive selection and domesticated strains grow more rapidly than extant wild strains. To assess physiological pathways altered by domestication, whole-genome mRNA expression was measured in brain, muscle and liver of size-matched domestic and wild trout using a 16K (cGRASP) salmonid microarray. A large number of genes differed between strains, ranging from 3% of genes in brain to 9% in muscle. Domestic fish had more down-regulated genes in the brain relative to wild fish, whereas more genes were up-regulated in domestic liver and muscle. Relative to wild fish, there was a down-regulation of cell division and an up-regulation of structural genes in the brain of domestic fish. In liver from domestic fish, there was an up-regulation of genes related to transport with a down-regulation of lipid binding. Analysis of the functional categories for muscle indicated that most pathways, including pathways related to metabolism and catabolism, were up-regulated in domestic fish. Comparison of these results to other genomic studies on transgenic, domestic and wild salmonids suggests that similar physiological pathways are altered systemically to support faster rates of growth, regardless of the underlying genetic alteration that has caused the altered growth. Microarray analyses were performed on nine individual fish per group of wild type and domestic rainbow trout hybridized (one slide per individual) against a common wild-type RNA pool.
Project description:Domestication has produced faster-growing strains of animals for use in agriculture, but selection has been applied with little knowledge of the underlying genetic changes that arose throughout the process. Mammals and birds have been domesticated for thousands of years whereas fish have been domesticated only recently; therefore, wild progenitor strains remain for comparison. Rainbow trout (Oncorhynchus mykiss) have undergone intensive selection and domesticated strains grow more rapidly than extant wild strains. To assess physiological pathways altered by domestication, whole-genome mRNA expression was measured in brain, muscle and liver of size-matched domestic and wild trout using a 16K (cGRASP) salmonid microarray. A large number of genes differed between strains, ranging from 3% of genes in brain to 9% in muscle. Domestic fish had more down-regulated genes in the brain relative to wild fish, whereas more genes were up-regulated in domestic liver and muscle. Relative to wild fish, there was a down-regulation of cell division and an up-regulation of structural genes in the brain of domestic fish. In liver from domestic fish, there was an up-regulation of genes related to transport with a down-regulation of lipid binding. Analysis of the functional categories for muscle indicated that most pathways, including pathways related to metabolism and catabolism, were up-regulated in domestic fish. Comparison of these results to other genomic studies on transgenic, domestic and wild salmonids suggests that similar physiological pathways are altered systemically to support faster rates of growth, regardless of the underlying genetic alteration that has caused the altered growth. Microarray analyses were performed on seven individual fish per group of wild type and domestic rainbow trout hybridized (one slide per individual) against a common wild-type RNA pool.