ANTHP 105 - Lecture Notes.docx - ANTHP 105 u2013 The Human...

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ANTHP 105 – The Human Species Chromosomes, Genes, & DNA; Genotype v. Phenotype8/25-8/291.Terms: Gene, Chromosome, DNA, base, Allele 2.Structure of DNA3.How are genes inherited?DNA: Deoxyribonucleic Acid Chromosome – long string of DNA, coiled into a dense, thick rodGene – a section of the chromosome that makes proteins or regulates other genes; functional sections of DNA since most of DNA is fillerProteins – Lego blocks of your body oGenes make those proteins or regulate other genes (turn them on/off to make more/less of a protein)Alleles are different versions of a geneThe bases of DNA A – Adenine T- ThymineG – GuanineC – Cytosine RNA: Ribonucleic Acid and FunctionsRNA is like DNAoHowever, it lacks T (Thymine) and instead contains U (Uracil)To make a protein, the DNA unzips exposing the bases on one sideA matching RNA strand is built, using the sequence of exposed DNA basesThe RNA goes off to build the proteinoDifferent sequence Different proteinsDNA bases are like letters Their sequences determine their functionReproductionmtDNA – a loop of DNA from the mitochondria46 chromosomes 23 pairs (this is normal)Meiosis – producing “gametes,” sperm and eggsIn sperm, mitochondrial DNA is on the tail Embryo has mtDNA from motherGenotype – the alleles that you have of the relevant genePhenotype – the way the gene is expressedHeterozygous – two different alleles on 2 chromosomesHomozygous – two same alleles on 2 chromosomes1
ANTHP 105 – The Human Species Simple v. Complex Traits8/29-9/8Mendel’s Rules of InheritanceWork for many simple traitsYou have 2 copies of each geneoOne inherited from the biological motheroOne from the biological father These may be the same alleles (versions of gene) or they may be differentoTogether, these alleles determine the phenotypeoAlleles may be dominant, recessive, or codominantDrDDD (Dominant)Dr (Dominant)rDr (Dominant)rr (Recessive)Ex. ABO Blood Type: A simple “Mendelian” TraitAlleles: A & B (Codominant), O (Recessive)GenotypePhenotype (Blood Type)AAAABAB (Codominant)AOABBBBOBOOOThe same can be applied to sex chromosomes. MOM – XXDAD – XYXXXXXXXYXYXYOffspring has 50% chance of being male and 50% chance of being female.What about – genes with only one copy? Pleiotropy: One gene influences many traits?Traits with many genes affecting them.How are traits determined?Simple Mendelian Traits: Genotype Phenotype 2
ANTHP 105 – The Human Species Complex Traits (most traits are like this)GenotypexEnvironmentPhenotype Often more than one gene affects a trait Ex. 200 genes affect heightEx. Diet, disease, temperature, light exposure,

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