Genetic Basis of Behaviour PDF
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Uploaded by sof
The University of Sheffield
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Summary
This document discusses the genetic basis of behavior in different animal species, focusing on examples such as snakes and mice. It explores how behavior is influenced by genetics and environment, and analyzes different experiments designed to study this. The document explains how artificial selection and gene knockouts can demonstrate evolutionary changes.
Full Transcript
*[Genetic basis of behaviour ]* Is behaviour genetic or learned? There are 5 main ways that have been used to test whether behaviour is genetic, learned or varying degrees of both. Variation between individuals of the same species- how much is genetic how much is environmental. 1. Studying naïve...
*[Genetic basis of behaviour ]* Is behaviour genetic or learned? There are 5 main ways that have been used to test whether behaviour is genetic, learned or varying degrees of both. Variation between individuals of the same species- how much is genetic how much is environmental. 1. Studying naïve youngsters - Newborn snakes were tested with chunks of slug and swabs of slug mucus. - if feeding choice is genetic, baby inland snakes would eat NOT eat the coastal slugs. - Very few baby inland snakes the slugs (\ - High line- nest should steadily increase - Low line- nest should steadily decrease - Control- no change The results showed that the high line mice would collect much more, and the low line collected less, the control also stayed the same as predicted. She repeated the experiment to ensure the results were robust and repeatable. This allowed her to demonstrate evolution in the lab and was able to decrease nest size by changing genes at her will. This proved that selection for a certain trait can only lead to a certain evolutionary response if the variation in that trait has a genetic basis. Increase in the frequency of fitness- enhancing alleles at the expense of other alleles *[Maintenance of genetic variation in behaviour]* If members of the species live in different local environments and in different conditions, they may experience different local selection pressures and so may develop different phenotypes. - Twins can be monozygotic or dizygotic twins. The tendency to produce dizygotic twins is partially heritable due to the genes causing a woman to ovulate 2 eggs at once rather than just one - In Finland, twins are exceptionally common in islands where there is predictable twin - Twins are less common on the mainland areas where famine is common. - Before modern medicine, twins had a high mortality rate, and so only paid off in better conditions - Genetic tendency towards twin birth is more common on the islands due to larger brood size - Different local selection pressures keeps this trait occurring
