Transcript Introx
Do now: pick up notes! Why do these things look the way they do? Deoxyribose Nucleic Acid DNA! Before these organisms were fully grown, multicellular organisms they INHERITED genetic information from an earlier generation which TOLD THEM HOW TO BECOME WHAT THEY ARE. GENETICS Your HOW-TO book. Resources Stated clearly http://www.statedclearly.com/ Geneticshttp://www.brainpop.com/science/cellularlifeandgenetics/gene tics/ Heredity http://www.brainpop.com/health/geneticsgrowthanddevelopm ent/heredity/ DNAhttp://www.brainpop.com/science/cellularlifeandgenetics/dna/ DNA mutations http://www.brainpop.com/health/geneticsgrowthanddevelopm ent/geneticmutations/ RNA http://www.brainpop.com/health/geneticsgrow thanddevelopment/rna/ Dolly http://www.brainpop.com/science/diversityoflif e/dollythesheep/ Cloning http://www.brainpop.com/science/cellularlifea ndgenetics/cloning/ 1. The Basics. During sexual reproduction gametes mix genetic content to form a new unique offspring The genetic information that is passed down to offspring is inherited information Think of an inheritance! $ Genes are units of inheritance or sections of DNA that code for particular traits The Basics. All organisms have TRAITS Trait – a specific characteristic Example: Eye color These traits are inherited from parents Traits have different ALLELES Allele – different forms of a trait Examples: Blue, green, brown, hazel The Basics. Some traits are DOMINANT When a trait is dominant it is ALWAYS expressed Some are traits are RECESSIVE Not always expressed, hidden The Basics. A GENE (basic unit of inheritance, distinct section of DNA molecule) that is dominant may not be a more “popular” gene Dominant alleles are always expressed with CAPITAL LETTERS Recessive alleles are always expressed with lower case letters The Basics. The two letters for each trait you inherit are called your GENOTYPE (think GENES, what is written in your DNA) The way you look – how the gene is physically expressed: phenotype! Something you can take a picture of! When is an allele expressed? DOMINANT EXPRESSED RECESSIVE EXPRESSED Needs only one dominant allele TT Tt Needs both recessive alleles tt Are dominant traits more frequently observed? Human Traits Survey Activity Define all the terms except for locus Answer the pre-activity question First determine and record your and your partners phenotypes. Use the backside of the sheet! Next identify possible genotypes that match your phenotype Remember: TT, Tt are possibilities for dominant! tt is recessive! Report your findings to Ms. Franchino Record class data Answer analysis questions Let’s check it out … Trait Dominance? Class Totals BENT PINKY Brown EYES MID-DIGITAL HAIR TONGUE ROLLING WIDOW’S PEAK D D D 3 10 7 D 9 D 1 FREE EAR LOBES CLEFT CHIN DIMPLES D D D 7 0 3 BENT THUMB D 6 FRECKLES D 2 What did you find? Not all dominant traits ALWAYS occur the most frequently. So then what does it mean to be a “dominant” allele if it’s not about how many people or organisms have it? Review! The way you look – how the gene is physically expressed: Phenotype (Something you can take a picture of) What you inherited : Genotype Terms for combinations HOMOZYGOUS HETEROZYGOUS Inherit two identical alleles Homo = same TT tt Inherit two different alleles Hetero – different Tt What does this picture say to you? Try to use the keywords we learned in class today: Dominant Recessive Traits Heredity DNA Probability of Inheritance Predicting Phenotypes PUNNETT SQUARE – Used to predict the probability of a trait occurring in offspring Pedigrees Besides predicting the probability of an organism inheriting a certain trait we can trace traits or disorders through family lineage called pedigrees Gregor Mendel first established the basis for genetics He determined that alleles for genes were either dominant and expressed when present or recessive and expressed only when two recessive alleles were inherited Further development in the field of genetics has given us greater insight to how alleles actually work We have found alleles that are not fully dominant, can blend with one another, and traits that require more than two alleles for expression Co dominance What does the root “co” mean? Think coworker, cooperate Co dominance This is when both alleles contribute to the phenotype of an organism Phenotype is a mix of the two traits Incomplete Dominance This is a blend between the two dominances REMEMBER Phenotype of an organism is only partially determined by the genotype Many traits are strongly influenced by the environment and nongenetic factors such as diet and exercise I.E. – nutritional improvements in the U.S. and Europe have increased the average height of these populations by about 10 centimeters over the average height in the 1800’s Selective Breeding Breeding that allows only animals with desired characteristics to produce offspring Hybridization – crossing similar organisms to get the best of both organisms Inbreeding – continued breeding of individuals with similar characteristics (breeds of dogs – beagles, poodles, etc.) Selective Breeding Used for show animals! Genetic Engineering Scientists can manipulate the DNA of organisms to create new or different species and characteristics Genetic engineering has led to the development of biotechnology or the technology of biology Increasing Variation A mutation is an inheritable change in DNA By mutating DNA of bacteria scientists have created organisms that can digest oil By limiting separation of chromosomes in plants undergoing meiosis scientists have created plants that are POLYPLOIDY Remember – haploid = half, diploid = 2, what would POLYploidy be? These plants are often larger and stronger than their diploid counterpart Transgenic Organisms Scientists take the genes from one organism and insert them into another Transgenic microorganisms are used to create insulin, human growth hormone, and clotting factors Transgenic animals grow faster and produce more meat with less fat Transgenic plants create their own synthetic insecticide or are resistant to weed killers GMOs Genetically Modified Organisms Plants and animals created from gene splicing In the U.S., GMOs are in as much as 80% of conventional processed food (http://www.nongmoproject.org/learn-more/) Cloning A clone is a member of a population of genetically identical cells produced from a single cell CLONING Dolly http://www.brainpop.com/science/diversityoflif e/dollythesheep/ Cloning http://www.brainpop.com/science/cellularlifea ndgenetics/cloning/ 1. Multiple Alleles Some traits, such as ear shape and eye color are not determined by just one gene These traits are considered polygenic, they require more than one gene One example of this in humans is blood type 2. Blood Type Influenced by MANY genes MOST important are ABO genes and Rh ABO Can be A, B, AB, or O Rh Can be + or – Total A+, combinations: A-, B+, B-, AB+, AB-, O+, O- 3. Sex Linked Genes 3. Sex linked genes Certain genes, diseases, or disorders are found only on the X chromosome A woman who inherits one afflicted X chromosome will not phenotypically display the trait A male who inherits one afflicated X chromosome will Sex-linked Traits 48 Traits (genes) located on the sex chromosomes Sex chromosomes are X and Y XX genotype for females XY genotype for males Many sex-linked traits carried on X chromosome Sex-linked Traits 49 Example: Eye color in fruit flies Sex Chromosomes fruit fly eye color XX chromosome - female Xy chromosome - male Female Carriers 50 SHHH!!! Write down what you see!! Sex linked traits Color blindness Inability to differentiate between certain shades or hues Hemophilia Lack of clotting factors Bleed out very easily 5. Linkage and Gene Maps Mapping the Genome Scientists are currently working to “map” the genome What do you think this means? Why would we need a “map” of our DNA? Mapping the genome It’s important to map our genome so that we can better understand our own genes How can we improve our genes or make them work more efficiently? DNA splicing