Anthro2050 1st Edition Lecture 11 Outline of Last Lecture I The American Eugenics Movement Outline of Current Lecture II Non Mendelian Genetics Current Lecture Genetic research in the 1930s and 1940s gave some new ideas about genetics outside of Mendel s research This helped bridge the gap between genetics and natural selection and showed how variation occurs through natural selection Changes in genetic information gets passed on to new generations through the laws of natural selection thus allowing genetic variation and evolution to occur Chromosome theory states that this genetic information is passed along our chromosomes with thousands of genes situated on 46 chromosomes Linkage when genes that are located close together on a chromosome get linked or stuck together causing the traits they control to be inherited together Crossing Over while some things are linked some are not and during meiosis they can become unstuck and some of the mother s alleles may become physically joined to some of the father s alleles Environment can also heavily influence genetics outcome Height for example is controlled by 7 genes that play a relatively small role to final height outcome A person s diet hormonal changes and certain diseases they may get in adolescence can influence their height as well Polygenic inheritance unlike in Mendelian theory most traits are controlled by multiple genes which allows for greater distribution of variety If a trait like skin colour for example was only controlled by one gene everyone on earth would either be extremely pale or extremely dark However since there are multiple genes controlling skin colour we get a wide distribution of skin tones around the world ranging from extremely pale to extremely dark and everywhere in between These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Unit characteristics traits controlled by one unit or one specific gene Places traits into categories that are each believed to be controlled by a gene whereas in reality some traits we think of in humans are not controlled by genes By sheer luck the traits on the pea plants that Mendel decided to look at were unit characteristics which is why he and others got the idea that all traits were controlled by one gene Pleiotropy not only are most traits controlled by multiple genes genes can each control or affect more than one trait or outcome These extra traits are usually hidden unless combined with other traits or exposed to certain environmental factors This is why someone may live healthily then one day suddenly have a genetically caused disease A gene that they have for one effect produced another effect that interacted with environmental factors to cause the disease Imprinting Some traits require specific genes from each parent to work together to make that trait If for some reason one parent s gene gets lost or deleted the other parent s gene is left alone and cannot function properly leading to defects such as Angelman Syndrome and ProderWilli Syndrome
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