ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 ChimeIn What do you think about cilantro In your opinion cilantro is A Delicious especially in guacamole B Gross tastes like soap C Meh I guess its ok Login to Canvas and click on the In Lecture Chime In link on the course homepage Load ChimeIn questions in a new window ANTH 1001 Fall 2023 Announcements Reminders Pre lab quiz 2 is due this Sunday Sept 17 at 11 59 pm 1 2 Gorilla selfies with a GoPro courtesy of Melbourne Zoo 2 1 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Review Darwin Wallace s ideas about how species change Descent with modification Evolution by natural selection Three necessary conditions for selection to occur Adaptations Review Genetics and inheritance Two functions of DNA Replication Protein synthesis 3 4 https flickr com photos 33398884 N03 4352531997 3 Image Khan Academy 4 2 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Review Genetics and inheritance Two functions of DNA Replication Protein synthesis Sources of genetic variation Mutation new alleles Recombination new combinations of alleles 5 6 ANTH 1001 HUMAN EVOLUTION MECHANISMS OF EVOLUTION II Maria Nieves Col n Gilbert Tostevin Department of Anthropology University of Minnesota 6 5 3 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Genes and traits Gene the DNA sequence that influences a trait by coding for a protein How many genes 7 8 8 4 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Genes and traits Monogenic traits are controlled by a single gene Genes and traits Monogenic traits are controlled by a single gene Polygenic traits are controlled by multiple genes 9 10 9 10 5 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Genes and traits Monogenic traits are controlled by a single gene Polygenic traits are controlled by multiple genes Pleiotropic traits are several traits controlled by a single gene 11 12 Dominant vs Recessive Dominant only one copy of the allele is needed to be expressed in the phenotype usually written in capital letters AA SS HH Recessive two copies are needed to be expressed in phenotype usually written in small letters aa ss hh Example lactase tolerance in humans AA homozygote Aa heterozygote aa homozygote 12 11 6 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Are dominant alleles or recessive alleles more frequent in a population better adapted to the environment more important for individual survival normal NO 13 Non coding DNA Only 2 of the human genome contains protein coding genes The rest is non coding DNA which does not produce proteins What is this non coding DNA doing 13 14 98 non coding 14 14 7 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Non coding DNA Genes are not static They can turn on and off and even regulate their expression like a dimmer switch regulates the intensity of lights A lot of non coding DNA is involved in gene regulation 15 16 So why do we need to understand genetics to study evolution 15 16 8 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 What do we mean by evolution In population genetics evolution is defined as a change in allele frequencies over time Gene Basic unit of heredity Allele Different forms of a gene If the relative amounts of alleles for a gene change from one generation to the next then we can say that evolution has occurred If ice cream were a gene the alleles would be all the different flavors Example hair color Allele Freq Black Blond Brown P generation 30 30 30 Red 10 17 18 9 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Example hair color The change in allele frequencies indicates that evolution has occurred Allele Freq P generation F1 generation Black Blond Brown 30 20 30 35 30 25 Red 10 20 19 20 Mechanisms of evolution If we define evolution as a change in allele frequencies through time then there are four mechanisms forces of evolution that will produce and redistribute variation in a population Mutation Gene flow Genetic drift Natural selection 10 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Evolutionary Mechanism 1 Mutation Any alteration in the genetic material or processes In evolution we are primarily concerned with those mutations that affect the germline gametes How will mutation affect variation within a population between among populations ChimeIn What do you think about cilantro 21 22 In your opinion cilantro is A Delicious especially in guacamole B Gross tastes like soap C Meh I guess its ok Login to Canvas and click on the In Lecture Chime In link on the course homepage Load ChimeIn questions in a new window ANTH 1001 Fall 2023 11 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Evolutionary Mechanism 1 Mutation example Olfactory receptor genes influence odor and taste perception People with a mutation on the OR6A2 gene chromosome 11 can easily detect aldehydes chemical compounds found in most soaps and in cilantro 23 24 Evolutionary Mechanism 1 Mutation example Olfactory receptor genes influence odor and taste perception People with a mutation on the OR6A2 gene chromosome 11 can easily detect aldehydes chemical compounds found in most soaps and in cilantro Frequencies of the soapy taste allele vary across human populations Allele frequencies at SNP rs72921001 in global populations Source Geography of Genetic Variants Browser 12 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Mutation Increase or decrease variation 25 26 Evolutionary Mechanism 2 Gene Flow Movement of genetic material from one population to another Can occur due to migration between populations How will gene flow affect variation within a population between among populations Gene flow in action new alleles being introduced to a population 13 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Evolutionary Mechanism 2 Gene Flow example Homo sapiens encountered Neanderthals when our species first moved into Eurasia 50 65 000 years ago Image Nicholas Prim Shuttershock for The Conversation Evolutionary Mechanism 2 Gene Flow example Homo sapiens encountered Neanderthals when our species first moved into Eurasia 50 65 000 years ago Several instances of gene flow occurred between Neanderthals and Homo sapiens Some of the alleles we acquired from Neanderthals help us fight off viral infections today 27 28 Source Enard Petrov 2018 14 ANTH1001 Human Evolution Nieves Col n Tostevin Fall 2023 Gene Flow Increase or decrease variation 29 30 Evolutionary Mechanism 3 Genetic
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