Home Topics Genetic Drift vs. Gene Flow vs. Natural Selection


Gardnerella vaginalis

Gardnerella Vaginalis

Definition Gardnerella vaginalis is the name of a micro-aerophilic coccobacillus found in the vaginal flora. Gardnerella vaginalis does not cause bacterial vaginosis (vaginal infection) unless...
Acetic Acid

Acetic Acid

Definition Acetic acid is a mildly corrosive monocarboxylic acid. Otherwise known as ethanoic acid, methanecarboxylic acid, hydrogen acetate or ethylic acid, this organic compound is...
Amino Acids

Amino Acids

Definition Amino acids are the building blocks of polypeptides and proteins and play important roles in metabolic pathway, gene expression, and cell signal transduction regulation....
BCAA supplements: a muscle myth?

Branched Chain Amino Acids

Definition The branched-chain amino acids or BCAAs, leucine, isoleucine, and valine are three of the nine nutritionally essential amino acids. These three ingredients form a...
Sulfuric acid

Sulfuric Acid

Definition Sulfuric acid (sulphuric acid) is a corrosive mineral acid with an oily, glassy appearance that gave it its earlier name of oil of vitriol....
Bile salt action in the gut

Bile Salts

Definition Bile salts are found in bile, a secretion produced by liver cells to aid digestion. Although bile is 95% water, bile salts are its...
The salivary glands

Submandibular Gland

Definition Submandibular glands are the second-largest salivary gland type, producing around 65% of our saliva when unstimulated (at rest). Located under the jaw, the exocrine...
Metaphase I

Metaphase I

Definition The first metaphase of meisosis I encompasses the alignment of paired chromosomes along the center (metaphase plate) of a cell, ensuring that two complete...
Prophase II

Prophase II

Definition During prophase II of meiosis II, four important steps occur. These are the condensing of chromatin into chromosomes, disintegration of the nuclear envelope, migration...


Definition Aldosterone (C21H28O5) is a mineralocorticoid hormone compound secreted by the adrenal gland cortex. It is part of the renin angiotensin aldosterone system or RAAS...

Genetic Drift vs. Gene Flow vs. Natural Selection

Genetic drift, gene flow, and natural selection may sound similar or even confusing to some. All three are mechanisms in the evolutionary process that have to do with alleles and/or gametes, but there are several significant differences.

Discussions about genes and natural selection usually include the term allele. An allele is just one version of a gene found at the same place (locus) on a chromosome. An example of an allele is the color of a bird’s feathers. In sexually reproducing organisms, alleles occur in pairs because the offspring receive one from each parent.

Genetic Drift

In genetic drift, alleles change frequency within a population due to random sampling. As a result, it does not produce adaptations. Two mechanisms cause genetic drift. The first is the bottle effect. This is genetic drift in a population after it has gone through a catastrophic event like a flood. The bottleneck happens when the allele frequency of a main trait in the original population is reduced because so many individuals carrying the allele have died. This causes most of the surviving population to die off, leaving a few random individuals as survivors. The other mechanism is called the founder effect. This is when a few members of a population break away and create their own group. Because of the random sampling that created the new group, the allele frequency can dramatically shift depending on the selective pressures place on the individuals.

Gene Flow

Gene flow differs from genetic drift because it is the transfer of alleles or gametes from one population to another. It happens when a population migrates or becomes geographically isolated. This is different from the genetic drift seen with the founder effect where the new group is formed in an area that does not have an existing population.

Natural Selection

Natural selection is like genetic drift but with one major difference—it’s not random. And unlike genetic drift which can be helpful, detrimental, or have no effect, natural selection represents only positive change/adaptation. Also, natural selection is influenced by changes in environmental conditions while genetic drift is random and based on luck. One major way gene flow is different from natural selection is that gene flow helps keep alleles in a population homogenized while natural selection increases genetic variation and always moves toward creating new species.


  • A Quick Genetic Drift vs Gene Flow vs Natural Selection Comparison. (n.d.). In Biology Wise. Retrieved from https://biologywise.com/genetic-drift-vs-gene-flow-vs-natural-selection