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Sewall Wright

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description Sewall Wright Overview

Sewall Wright was a pivotal 20th-century American biologist known for his foundational work in population genetics. He significantly advanced theoretical genetics through rigorous mathematical modeling, particularly concerning genetic drift and its impact on allele frequencies within populations. His research profoundly influenced evolutionary biology and remains essential for understanding the dynamics of inherited traits across diverse groups, especially those studying genetics and population studies.

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What did Sewall Wright mean by genetic drift?

Genetic drift is a random change in allele frequencies caused by chance births, deaths, and reproduction rather than by natural selection. Wright's mathematical work showed why these effects can be especially strong in small populations, as summarized by [Nature](https://www.nature.com/scitable/topicpage/sewall-wright-and-the-development-of-shifting-30508/).

What is Sewall Wright's adaptive landscape?

The adaptive landscape is a model that represents population fitness as a surface with higher and lower points, often described as fitness peaks and valleys. Wright introduced the idea in a 1932 diagram to explain how selection, drift, and gene combinations can influence evolutionary paths.

What was Sewall Wright's shifting balance theory?

Wright proposed that small, partly isolated populations could move through an adaptive landscape by genetic drift, then improve through natural selection and migration. The theory connected population structure with the movement between different fitness peaks.

Which other population-genetic forces did Sewall Wright model?

His work covered inbreeding, mating systems, selection, mutation, migration, and random genetic drift. By combining these forces mathematically, Wright helped establish theoretical population genetics as a modern field.