Question
Asked 8th Jul, 2014

What is the difference between positive and negative selection pressure?

How do we differentiate between positive and negative selection. These two terms sound like they are complementary to each other.

Most recent answer

29th Sep, 2018
Alexander Igoshin
Institute of Cytology and Genetics
It's all relative. What about the situation in which selection acts on standing variation and an ancestral allele is preferred? We can say it is purifying selection, because the derived allele is being eliminated. We also can say that it is positive selection because the ancestral allele is driven to high frequency and a selective sweep is produced.
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Popular Answers (1)

21st Jan, 2015
Andrea Gazzola
University of Pavia
Positive selection: also called (Darwinian selection) variants that increase in frequency until they fix in the relevant population. The selective pressure that leads to this fixation is termed positive selection.
Negative selection: Also called purifying selection, it means that selection is purging changes that cause deleterious impacts on the fitness of the host.
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All Answers (6)

8th Jul, 2014
Silvio Erler
Julius Kühn-Institut Braunschweig
positive selection = positive, directional selection
negative selection = purifying selection
This review might help.
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8th Jul, 2014
C. S. Mukhopadhyay
Guru Angad Dev Veterinary and Animal Sciences University
@ Artur & Silivo, thanks for your best possible replies.
21st Jan, 2015
Andrea Gazzola
University of Pavia
Positive selection: also called (Darwinian selection) variants that increase in frequency until they fix in the relevant population. The selective pressure that leads to this fixation is termed positive selection.
Negative selection: Also called purifying selection, it means that selection is purging changes that cause deleterious impacts on the fitness of the host.
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21st Jan, 2015
C. S. Mukhopadhyay
Guru Angad Dev Veterinary and Animal Sciences University
@Dr Andrea Gazolla, thanks for the note.
2nd Mar, 2016
Georgi Gladyshev
Russian Academy of Sciences
Variation and selection depend from the non-spontaneous and spontaneous processes. The hierarchical thermodynamics determines the direction of evolution and aging of living beings. Please see: On the physical - chemical basis of Darwinism https://www.researchgate.net/profile/Georgi_Gladyshev .....
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