Positive Selection Screen
Positive Selection Screen - Related Videos
14:29
Examination of Thymic Positive and Negative Selection by Flow Cytometry
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Cited by 22 •
2012
We present a flow cytometry-based method to examine T cell development in vivo using genetically manipulated mice on a wildtype or T cell receptor transgenic background.
07:28
Photodegradable Hydrogel Interfaces for Bacteria Screening, Selection, and Isolation
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Cited by 6 •
2021
The use of photodegradable hydrogels to isolate bacterial cells by utilizing a high-resolution light pattering tool is reported. Essential experimental procedures, results, and advantages of the process are reviewed. The method enables rapid and inexpensive isolation of targeted bacteria showing rare or unique functions from heterogeneous communities or populations.
09:44
High-throughput Screening for Chemical Modulators of Post-transcriptionally Regulated Genes
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2015
Here we describe a cell-based reporter gene assay as a valuable tool to screen chemical libraries for compounds modulating post-transcriptional control mechanisms exerted through 3’ UTR.
03:14
Artificial Selection - Concepts
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2019
Natural Selection and Adaptive Evolution In natural settings, adaptive evolution takes place by natural selection, a process in which differences in traits lead to differences in survival and reproductive success between individuals. This happens because individuals with certain phenotypes have a higher probability of survival and/or produce more surviving offspring than individuals with other phenotypes. A classic example of this was demonstrated by Rosemary and Peter Grant studying the...
07:06
Positive Reinforcement Studies
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2023
Researchers study learning of a behavior through the use of operant conditioning. This type of learning involves associating the behavior with a consequence, which is a reward or punishment. If the consequence is a reward, it leads to reinforcement of the desired behavior. One type of reinforcement approach is positive reinforcement, where the behavior is rewarded with an artificial, natural, or social reinforcer. Studies using positive reinforcement as a tool can help tease out important...
FAQs
The marker creates a direct link between genotype and growth under a defined selective condition. When the target alteration activates antibiotic resistance or restores an essential function, cells carrying that alteration can continue proliferating, whereas cells lacking it are inhibited. This coupling converts a genetic difference into an observable growth outcome that can be used for enrichment.
Selective conditions determine whether the marker can distinguish altered cells from the surrounding population. The condition must inhibit cells that lack the desired genetic change while permitting cells with the linked marker function to grow. When that relationship is effective, selection concentrates the population around candidate cells instead of requiring researchers to identify rare events individually.
A positive selection screen enriches cells that have acquired the relevant alteration, allowing those cells to proliferate while unsuccessful cells are inhibited. This is especially valuable when the desired event occurs infrequently among many unaltered cells. The resulting enrichment simplifies recovery of candidate transformants, insertion events, or successful genome-editing outcomes.
The general workflow links a desired genetic alteration to a selectable marker, exposes the cell population to the corresponding selective condition, and recovers cells that survive and grow. Researchers then use the enriched population as the source of candidate genetic events. The approach therefore moves from marker-based selection to growth-based recovery rather than direct inspection of every cell.
Researchers apply positive selection when they need to isolate cells carrying a particular genetic change from a larger population. In molecular genetics, it can recover transformed cells and gene-insertion events. In genome-editing studies, the same principle helps enrich successful editing outcomes, while functional genomics and biotechnology use it to connect genetic changes with recoverable cell growth.
The immediate outcome is an enriched population of cells that survived and proliferated under the chosen selective condition. Because survival is tied to a selectable marker, the recovered cells represent candidates carrying the desired genetic change. This provides a practical entry point for studying transformed cells, insertion events, or genome-editing outcomes in biological research.