Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Genetic Vocabularywhat is a Genome?The total genetic endowment of a specieswhat do we call the alleles YOU possess? –your individual genetic makeup?genotypeThe alleles you posses define your genotypeor hereditary makeup.The way they are expressed physically is calledwhat? You can’t always tell a person’s genotypefrom what you see on the outside,from their phenotypeyour phenotype: the sum of observable traits.Homozygous: both alleles in the pair arethe sameHeterozygous: two different alleles in a pairRemember, one allele in the pair will come fromyour mother, and one from your fatherThe alleles you posses define your genotypeor hereditary makeup.The way they are expressed physically is yourphenotype: the sum of observable traits.When you have heterozygous allelesRecessive: the allele in the pair that is notexpressed in your phenotypeDominant: the allele in the pair that isthe only one expressed in your phenotypeCo-dominant: both alleles are partiallyexpressedAny particular trait can be determinedby any number of loci:Single gene trait = monogenic inheritance Polygenic inheritance = two or more genes work together to affect some trait/characterHemoglobin by 2 lociSkin color by many -- we don’t know how manyMonogenic trait:Trait affected by change at only one locusEven though it is a change in only onelocus, it may have many phenotypic effects.Example: albinismAffects skin, hair, eyesOn top of that,environmental factors may play a role in producing many phenotypic traits: cancer, sunburn, bad eyesPoint mutation:A mutation of single codon, or sometimesof a single base in a codonExample: Sickle cell anemiaresults in abnormal blood cellsnormalsickle•kvhs.nbed.nb.ca/gallant/biology/point_mutation.html Results from a mutation on chromosome 11:the amino acid valine is substituted forglutamic acid at position 6Macromutation: a mutation with important or far-reaching results. Example: change in the rate of developmentThis is the kind of mutation hypothesizedto have played a critical role in the development of bipedalism in humansPolygenic traits:Traits affected by more than one genePolygenic traits are least easy to figure out, and are also affected by the environment.Example: statureIn most cases, we don’t have a clear idea of the way polygenes combine to influence a trait. Keep in mind that many of the traits we’ll be examining in our study of human evolution are far from simple: they often are polygenic traits. The transmission of polygenic traits tends to produce intermediate phenotypes.http://openlearn.open.ac.uk/mod/resource/view.php?id=193030Sex-linked genes:Genes that occur only on the X or Y chromosomeUnlike other chromosomes, which occur inhomologous pairs, there are two differenttypes of sex chromosomesThe X chromosome carries a lot ofhereditary information, but the Y seemsto specify little apart from sexSex-linked genes are significant when theyinvolve a harmful recessive gene:The male will express that trait becausethere is no dominant allele to suppress itExample: red-green color blindnessThis trait is carried on the X chromosome.A female may be a carrier but not express it.She has a 50-50 chance of passing it on toher son.Sex-linked genes:Another example: hemophiliaQueen Victoria was a carrier:4/9 children; 8/26 grandchildren; 6/34 great-grandchildren Normally fatal and would be lost. But occursas a mutation c. every 50,000 parentsQuick Review of Basic Geneticsfor Understanding EvolutionA mutation with far-reaching effects,one that could begin a new species, is called a:macromutationA trait affected by a single gene is called a:monogenic traitTraits with intermediate types are oftenaffected by one gene, or by multiple genes?They are often polygenic traits,affected by more than one geneA gene that occurs only on the Xchromosome is what kind of gene?A sex-linked geneIf a harmful, recessive gene occurs on the Xchromosome of a male, will it be evident fromhis phenotype?Yes, because there is no correspondingallele that could mask it.“A change in the allele frequency of a populationover time” is the definition of what word?evolutionWhat is the source of different alleles?mutationWhat are the sources of individual variationfrom generation to generation, due tosexual reproduction?1. Mutation2. Segregation/Independent assortment3. Crossing over, leading to recombination4. Linked genesThe total genes of a population is called:Gene poolWhat is a population?a group of individuals that interbreedsWhat is a species?A population or group of populations that is capable of interbreeding and is reproductively isolated from other populations.A group of organisms that can produce fertileoffspring among themselves, but not with other groupsWhat does the Hardy-Weinberg Equilibrium Principle state?That evolution will NOT happen(the allele frequency of a population will NOT change) IFFour conditions are metMating is entirely randomThe population is large enoughNo new variants are introduced into the gene poolAll individuals are equally successful at surviving and reproducingWhat are the four conditions that, if met,would lead to no change in the gene poolof a population from one generation to another?No geographic or social barriersNo genetic drift (skewing due to small population size)No mutations, no gene flowNo natural selection forcesWhat are the sources of change in apopulation over time (what are themechanisms of evolution)?1. Mutation2. Natural selection3. Genetic drift4. Gene flowWhat do we call the introduction of newgenetic material into a population?Gene flowWhat do we call the free or wide-rangingexchange of genetic material within a population?Gene flowTRUE/FALSENatural selection is constantly changing anyone species, making it “evolve”FALSE. Only when the environment orselective forces change, will natural selectionwork to advantage a different range of alleles.Otherwise, we may seeStabilizing selection:Natural selection promotes stability becausethere is no environmental change OrOscillating selection:Adaptive variation around a norm, in responseto environmental variationWhat is the result when a group out of a populationsplits away, taking their alleles out of the maingene pool?Genetic driftGenetic driftWhat do we call a change in
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