Generally, biological replicates are defined as measurements of biologically distinct samples that show biological variation (21). In contrast, technical replicates are repeated measurements of the same sample that show independent measures of the noise associated with the equipment and the protocols.
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What is considered biological replicate in cell culture?
Biological replicates, on the other hand, are independently repeated experiments performed on cells of the same cell line but derived from a biologically distinct source or of a different passage.
Are biological replicates independent experiments?
As biological experiments can be complicated, replicate measurements are often taken to monitor the performance of the experiment, but such replicates are not independent tests of the hypothesis, and so they cannot provide evidence of the reproducibility of the main results.
What is the purpose of biological replicates?
Biological replicates are different samples measured across multiple conditions, e.g., six different human samples across six arrays. Using replicates offers three major advantages: Replicates can be used to measure variation in the experiment so that statistical tests can be applied to evaluate differences.
How many biological replicates are there?
For future RNA-seq experiments, these results suggest that at least six biological replicates should be used, rising to at least 12 when it is important to identify SDE genes for all fold changes.
How do you combine technical and biological replicates?
Combine each technical replicates for each biological replicate, then combine each biological replicate into a group (i.e. treated group or baseline group). Remember technical replicates are there for measuring variability resultant from pipetting, whilst biological replicates for biological variation in expression.
How many biological and technical replicates are there?
(a) Three levels of replication (two biological, one technical) with animal, cell and measurement replicates normally distributed with a mean across animals of 10 and ratio of variances 1:2:0.5.
What does replicate mean in biology?
DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. Replication is an essential process because, whenever a cell divides, the two new daughter cells must contain the same genetic information, or DNA, as the parent cell.
What is an independent replicate?
Replicating the experiment by independent researchers. Repeating the whole experiment by researchers that were not part of the initial experiment. This occurs when a paper is published and others try to obtain the same results.
What is the difference between replicate and duplicate?
The word duplicate is derived from the Latin word duplicare, which means to double. Replicate means to reproduce something, to construct a copy of something, to make a facsimile. The word replicate may be interchangeable with the word duplicate except in a few instances.
How many replicates do you need to be a statistically sound experiment?
Normally we design experiment with 3 replicates, each replicate has like 10 samples/treatment (so total number of samples n = 30/treatment). Then we average the results of these 10 samples to get 1 number/replicate and use these 3 numbers/treatment to performing statistical analysis.
What is the difference between replication and repeated experiments?
Repeated measures involves measuring the same cases multiple times. So, if you measured the chips, then did something to them, then measured them again, etc it would be repeated measures. Replication involves running the same study on different subjects but identical conditions.
What type of conclusions can you draw from biological replicates?
Biological replicates are used in gene expression studies, so conclusions can be generalised to groups represented by the various individuals/sources that the samples were taken from.
What are the replicates in an experiment?
What is a replicate? Replicates are multiple experimental runs with the same factor settings (levels). Replicates are subject to the same sources of variability, independently of each other. You can replicate combinations of factor levels, groups of factor level combinations, or entire designs.
What is replicate sampling?
Field Replicates. Field replicate samples are defined as “Independent samples that are collected as close as possible to the same point in space and time.
How many biological replicates are needed in an RNA-seq?
For future RNA-seq experiments, these results suggest that at least six biological replicates should be used, rising to at least 12 when it is important to identify SDE genes for all fold changes.
What are biological replicates in RNA-seq?
In RNA-seq, an estimate of abundance is obtained for each feature. Biological replicates: Samples that have been obtained from biologically separate samples.
How many technical replicates should I have?
As for technical replicates, usually you will need 3 for each biological sample (also for positive and negative controls), and in a pinch it may be reduced to 2. You basically only need them to make sure that your reaction is reproducible.
How do you combine data from repeated experiments?
If you repeat the experiments on the same sample unit, you can combine the experiments as technical replication. If, on the other hand, each experiment repetition is performed on different sample units, then you can combine all experiments as one bigger experiment.
Should you average technical replicates?
Averaging technical replicates (as in the left panel) and running statistical analyses on average values means losing potentially important information. No facet should be dropped from analysis unless one is confident that it can have absolutely no effect on analyses.
Why do you repeat experiments 3 times?
Repeating an experiment more than once helps determine if the data was a fluke, or represents the normal case. It helps guard against jumping to conclusions without enough evidence. The number of repeats depends on many factors, including the spread of the data and the availability of resources.
What is DNA replication called?
The process of DNA duplication is called DNA replication. Replication follows several steps that involve multiple proteins called replication enzymes and RNA. In eukaryotic cells, such as animal cells and plant cells, DNA replication occurs in the S phase of interphase during the cell cycle.
Where does replication occur in biology?
DNA replication occurs in the nucleus in eukaryotic cells and in the nucleoid region of prokaryotic cells. Eukaryotic cells are cells that have a nucleus and membrane bound organelles, such as plant cells and animal cells. Eukaryotic cells contain their DNA in the nucleus, and thus this is where DNA replication occurs.
What does it mean to replicate a research study?
Replication is a study for which any outcome would be considered diagnostic evidence about a claim from prior research. This definition reduces emphasis on operational characteristics of the study and increases emphasis on the interpretation of possible outcomes.
What is the difference between a replicate and an experimental unit?
These three are terms used when multiple samples are taken from a single experimental unit. Replicate: A replicate is one experimental unit in one treatment. The number of replicates is the number of experimental units in a treatment.