Week Two ATY 253-01
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This 5 page Class Notes was uploaded by Amber Hall on Sunday August 30, 2015. The Class Notes belongs to ATY 253-01 at University of North Carolina - Greensboro taught by Charles P. Egeland in Spring 2015. Since its upload, it has received 17 views. For similar materials see Intro to Biological Anthrpolgy in Environmental Science at University of North Carolina - Greensboro.
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Date Created: 08/30/15
82515 ATY Lecture 3 How does inheritance work Natural selection can t see into the future and only acts on heritable variation Natural selection acts on individuals but populations evolve It s not the only force that generates change It s not foolproof Organisms are not quottryingquot to adapt Limitations to Darwin s Theory quotthe laws of inheritance are for the most part unknown Where does variation ultimately come from What about maladaptive traits How is variation maintained Blending inheritance ex Mixing buckets of paint Discovering Inheritance Gregor Mendel 18221884 o A monk living in Brno modern Czech Republic 0 Provided a mechanism for inheritance o Bred and crosspollinated pea plants Mendel s pea experiments 0 Traits don t blend 0 Inheritance is determined by physical quotunitsquot that are passed down unchanged 0 Offspring get one unit from each parent for each trait o Trait may not show up but can still be passed on 0 Results were forgotten for 40 years After Mendel Organisms are made of cells lack a nucleus ex Bacteria multiple cells and a cell nucleus Two types of cells 0 Somatic body cells 0 Gametes sex cells All cell nuclei have chromosomes Replicated during cell division Chromosomes Humans have 46 Paired diploid One from mom one from dad Homologous pairs 23 Autosomes Sex chromosomes Females XX 0 Males XY complete set of chromosomes 0 Cell division mitosis New cells have all chromosomes diploid Exact copies created Somatic cells Cell division meiosis All new cells have only one copy of each chromosome haploid Sex cells Haploid sperm haploid egg diploid zygote Genes and Chromosomes Thomas Hunt Morgan 0 Genes are on chromosomes I One copy of each chromosome from each parent I Meiosis creates gametes with only one pair of chromosomes Genes are like beads on a string Recombination of chromosomes during meiosis over 8 million possibilities Crossing over during meiosis Translocation Mendalian Genetics variant of gene ex Eye hair color two copies of same allele different alleles combination of alleles that an individual carries physical expression of genotype allele always expressed if present allele only expressed if dominant allele is absent 82715 ATY Lecture 4 Limitations to Darwin s theory Laws of inheritance unknown 1 Segregation each gamete only gets one copy of a gene 2 3 DominantRecessive only one allele is expressed in the phenotype Independent Assortment different traits are inherited independently of each other Where does variation come from 1 Recombination crossing over 2 Mutations How is variation maintained 1 Traits do not blend 2 Recombination crossing over mutations The Discovery of DNA deoxyribonucleic acid 1953 Rosalind Franklin Francis Crick James Watson quotdouble helix What does DNA do Library for creating and maintaining an organism The library can make copies of itself Each book carries the specific info for making proteins DNA s functions are permitted by its structure DNA Structure legs are sugar and phosphate molecules quotrungsquot are paired nitrogen bases Nucleotide 3 billion in each cell Bases adenine A thymine T guanine G cytosine C same for all life on earth A and T go together C and G go together DNA Replication Every time a new cell is created Growth and development Occurs in the cell nucleus Identical copies made Step 1 DNA quotunzipsquot Step 2 complimentary bases pair up Result 2 DNA strands Making Proteins DNA holds the books for creating proteins 0 Structural responsible for physical traits ex Keratin collagen Regulatory enzymes regulates chemical reactions Proteins are made of amino acids 0 Amino acids are associated with a 3 base code Amino acid DNA triplet code codon Lysine T39I39I39 39I39I39C 20 total amino acids Step 1 Transcription Body needs a protein 9 check out book by unzipping it in the nucleus 9 complimentary bases match up Step 2 Translation Copied DNA segment moves outside nucleus 9 codons match up to exposed segment 9 amino acids are bound together like a train Types of Genes Structural genes responsible for physical traits Regulatory genes turns genes on and off 0 Homeotic Hox genes I Guide the development of an organism s body I The structural genes are the same for fungi mice humans etc I Marfan Syndrome long appendages mutation More on genes Not all DNA is made up of genes Of 3 billion bases only 25 of genome is quotcodingquot The rest is either quotsilentquot or influences how genes are expressed complete set of genes in an individual cell Humans quot25000 genes Human Genome Project 2 or more alleles for a genetic trait Blood type gene has 3 alleles A B O A and B alleles are codominant One gene one protein 0 Monogenic traits ex Blood type redgreen color blindness dimples Many genes one protein 0 Polygenic traits ex Height skin color tooth size eye shape One gene many proteins 0 Pleiotropyphenylketonuria Many genes many proteins 0 Polygenic traits and pleiotropy most complex traits Gene expression is even more complex Environment can determine if or when genes are turn on or off switch vs dimmer genetics control by factors other than an individual s DNA sequences Sometimes your genes get tagged and these quottagsquot can be inherited Heritability proportion of a trait s variation that is genetic height 60 genetic weight 30 tooth size 70 some addictions 60