What is difference between GWAS and SNP?5 answersGenome-wide association studies (GWAS) and Single Nucleotide Polymorphisms (SNPs) are closely related concepts in genetic research. GWAS is a method used to identify genetic variants associated with traits or diseases by analyzing SNPs across the genome. SNPs, on the other hand, are variations in a single nucleotide that occur at a specific position in the genome and are commonly used as markers in GWAS to pinpoint regions linked to complex diseases or traits. While GWAS focuses on identifying associations between SNPs and traits, SNPs themselves are the specific genetic markers that are analyzed in GWAS to uncover genetic links to various phenotypes, making them integral components of genome-wide association studies.
Is there a GWAS on mice?5 answersYes, there are genome-wide association studies (GWAS) conducted on mice. GWAS in mice have been used to uncover host genetic factors for rare kidney traits such as collapsing glomerulopathy. The impact of population structure (PS) on murine GWAS results has been investigated, and it has been found that PS has minimal impact on datasets characterizing ≤20 strains and surprisingly little impact on datasets characterizing 21-40 inbred strains. The GWAS Central resource has expanded to include mouse gene-phenotype associations observed during mouse gene knockout screens, allowing for cross-species comparison of phenotypes. Mouse GWAS builds on linkage techniques and the known phenotypic differences in auditory function between inbred strains, providing valuable insights into aging and noise-induced sensorineural hearing loss and tinnitus. The use of Diversity Outbred (DO) mice has also advanced our understanding of the genetics of osteoporosis and informed human GWAS for bone traits.
How does small effective population size affect the genetic diversity of a population?4 answersSmall effective population size can have an impact on the genetic diversity of a population. In small populations, genetic drift occurs more frequently, leading to changes in allele frequencies and the loss of genetic variation. Inbreeding, which is more common in small populations, can also contribute to the loss of genetic variation and inbreeding depression. Coalescent-based models of genetic diversity tend to overestimate genetic diversity in small populations with very small effective sizes, especially when sampled soon after a decline. However, the magnitude of the bias in genetic diversity estimates due to small sample sizes is proportional to the effective population size and gene flow. Therefore, caution is needed when interpreting genetic patterns based on small sample sizes, particularly when the observed genetic differentiation is weak.
What are the advantages and disadvantages of using GWAS compared to linkage analysis?4 answersGenome-wide association studies (GWAS) and linkage analysis are two approaches used for mapping genes associated with complex traits. GWAS have the advantage of being able to capture a wide range of genetic variation across the genome, allowing for the identification of common variants associated with complex traits. They also have the ability to detect small effect sizes and can be performed in large populations. However, GWAS have limitations, including the need for a large sample size to achieve sufficient statistical power and the reliance on linkage disequilibrium (LD) to capture quantitative trait locus (QTL) signals. On the other hand, linkage analysis has been successful in mapping disease genes with clear patterns of Mendelian inheritance. It can also be used for mapping susceptibility genes for common complex diseases. However, linkage analysis is limited by the need for large families with multiple affected individuals and the inability to detect small effect sizes.
How sample size influences research outcomes?3 answersSample size has a significant impact on research outcomes. It is important to have an appropriate sample size that is neither too small nor too large. A study by Faber and Fonsecahighlights that different sample sizes can lead to different clinical decisions, even if the methodology and results are equivalent. Vozzi et al.found that reducing sample size resulted in a decrease in correlation, an increase in mean squared error and standard deviation, and a threshold for maintaining significant and comparable outcomes. Hoffart et al.discovered that sample size did not influence selling prices or confidence on average, but individual learning strategies and cognitive complexity played a role. Igundunasseobserved that varying sample sizes had different impacts on research outcomes in factor analytic studies. Ahrens and Zaščerinskaemphasized the importance of sample size in statistical analysis and generalization, but noted that factors influencing sample size in educational research have received little attention.
Will GWAS on viruses, bacteria, and oomycetes reveal a genetic architecture of pathogenicity different from GWAS on fungi?5 answersGWAS on viruses, bacteria, and oomycetes may reveal a different genetic architecture of pathogenicity compared to GWAS on fungi. The genetic architecture of pathogenicity can be influenced by interactions with environmental phagocytes, as seen in the "Amoeboid Predator-Fungal Animal Virulence Hypothesis". This hypothesis suggests that selection to avoid predation by amoeba can inadvertently select for traits that contribute to fungal escape from phagocytic immune cells. Additionally, GWAS studies in admixed populations have shown that differences in estimated allelic effect sizes for risk variants between ancestry backgrounds can impact association statistics. Therefore, it is possible that the genetic architecture of pathogenicity in viruses, bacteria, and oomycetes may be shaped by different factors and mechanisms compared to fungi. Further research is needed to explore these differences and understand the specific genetic architecture of pathogenicity in different microbial pathogens.