BIOL 120 Week 4 Notes
BIOL 120 Week 4 Notes BIOL120
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This 6 page Class Notes was uploaded by Julia Delaluz on Saturday March 5, 2016. The Class Notes belongs to BIOL120 at Towson University taught by Dr.Partain in Winter 2016. Since its upload, it has received 15 views. For similar materials see Principals of biology in Biology at Towson University.
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Date Created: 03/05/16
Julia Delaluz Christa Partain BIOL 120 Notes Week 4: (2/29 3/4) Extension of Mendelian Genetics 1. Incomplete Dominance 2. Co-dominance 3. Sex-linked traits 4. Multiple alleles 5. Environmental effects 6. Lethal Effects 7. Continuous Variation 8. One Gene has Multiple Effects 1. Incomplete Dominance: If a heterozygous genotype is present, then the phenotype is intermediate Aa genotype shows a mixture for phenotype: Hair curl A= straight, a= curly o AA= straight hair Aa= wavy hair aa= curly hair 2. Co-dominance: If a heterozygous genotype is present, both phenotypes exist side-by-side Both alleles are fully seen in the phenotype: Sickle cell hemoglobin N= normal, S= sickle o NN= all normal SS= all sickle NS= half normal half sickle 3. Sex-Linked Traits: Genes on the sex chromosomes usually on the X, but can be on the Y. The X chromosome is much larger than Y, which carries very little genetic info Differently affect males & females o Males more likely to suffer from diseases caused by recessive alleles on the X chromosome o because they only have 1 copy of the ex-linked gene Ex: hemophilia, red/green colorblindness. Diseases are usually recessive C= normal C= color blind Xc Xc Julia Delaluz Christa Partain BIOL 120 Notes Week 4: (2/29 3/4) Xc Xc Xc Xc Normal girlXc Punnett Carrier girl Square Y Normal boyXColorblind boy 4. Multiple Alleles: Have more than two possibilities for alleles ABO blood types: Both multiple alleles (IA IB and i) and co- dominance (IA and IB are co-dominant) O is genotype recessive 5. Environmental Effects: The environment can have an effect on how the genes are expressed Malnutrition and height Temperature/altitude and plant growth Siamese cats and Himalayan rabbits Environment determines the phenotypic pattern of expression Pigment production is able to only functions at lower temps of those extremities- like black coloring in rabbits 6. Lethal Alleles: A mutated allele that fails to code for the production of a functional protein that is vital for life The combination of two lethal alleles (usually recessive) cause death Albinism in corn plant Mexican hairless dogs (dominant) 7. Continuous Variation: Several genes working together producing many phenotypes for that trait Human eye color, skin color 8. One Gene: Multiple effects One gene can cause several different problems- sickle cell disease Julia Delaluz Christa Partain BIOL 120 Notes Week 4: (2/29 3/4) Autosomal (on chromosomes 1-22) Recessive o Tay Sachs, Cystic Fibrosis, PKU Dominant o Huntington Disease o Lactose Intolerance o Polydactyly X-Linked o Recessive Red/Green Color Blindness, hemophilia, muscular dystrophy o Dominant Hypertrichosis Julia Delaluz Christa Partain BIOL 120 Notes Week 4: (2/29 3/4) Mutations through Non-Disjunction Each species has a specific number of chromosomes PROBLEMS – chromosome number Non-Disjunction o Improper separation of chromosomes during cell division Somatic (mitosis) – only affects individual Germ (meiosis) – affects offspring Examples: o Autosomal: Trisomy 21- Down Syndrome o Sex Chromosomes: XO – missing 2 ndsex chromosome XXX – one extra X YO – lethal missing X XXY – one extra X male XYY – one extra Y Mutations affect protein synthesis o A protein specified by a mutated gene may have harmful, neutral, or beneficial effects on the ability of an individual to function in the prevailing environment o Types of mutations: Missense, nonsense, frameshift, deletion, duplication, insertion, expanding generation 1, expanding gen. 2, expanding gen. 3 Form & Function Chromosomes need to have a specific shape/carry the correct genes Problems with chromosome structure 1. Deletion: missing a gene 2. Inversion: upside down gene 3. Duplication: extra gene 4. Translocation: traded gene w/ other chromosome Studying Human Genetics Due to difficulty (long lifecycle/gestation & low number of offspring) & ethical issues, geneticists use records, such as family tree & pedigree Julia Delaluz Christa Partain BIOL 120 Notes Week 4: (2/29 3/4) Topics in Biotechnology How can we use our knowledge of DNA and heredity tour advantage and to improve our lifestyles and overcome disease? Genetic Engineering GMOS: o Recombinant Growth Hormones o Foods containing GMOS have been on the market since the 1990s o Its involved in more than 2/3 of foods sold in the US o 80% of hard cheeses sold in the US are made with enzymes created by genetically modified microbes o Roundup Ready© crops, BT (Bacillus thuringiensis) crops, Golden Corn o The new organism that’s formed is called a Transgenic Organism or GMO (Genetically Modified Organism) using Recombinant Technology- inserting genes from one type of organism into another Gene Therapy Stem Cell Cloning Modified Foods Increasing food nutritional value Preventing spoiling Preventing frost damage Prevent plant diseases Helping Humans Insulin: used to help diabetics BHG protein: blood clothing factor Fertility hormones: hormones used in fertility treatments to stimulate ovulation Human growth hormone Some vaccines Breeding sterile vectors such as mosquitoes Issues with Modified foods & Therapeutics Allergies Disease resistance Transgenic organisms breeding with native species Julia Delaluz Christa Partain BIOL 120 Notes Week 4: (2/29 3/4) Decreasing variation within a species Unexpected side effects