* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Genetics
Genetic testing wikipedia , lookup
Transgenerational epigenetic inheritance wikipedia , lookup
Minimal genome wikipedia , lookup
Polymorphism (biology) wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Human genetic variation wikipedia , lookup
Genome evolution wikipedia , lookup
Neocentromere wikipedia , lookup
Skewed X-inactivation wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Genetic drift wikipedia , lookup
Gene expression profiling wikipedia , lookup
Y chromosome wikipedia , lookup
Heritability of IQ wikipedia , lookup
Pharmacogenomics wikipedia , lookup
Population genetics wikipedia , lookup
Genetic engineering wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Behavioural genetics wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Medical genetics wikipedia , lookup
Gene expression programming wikipedia , lookup
Genomic imprinting wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Public health genomics wikipedia , lookup
History of genetic engineering wikipedia , lookup
Hardy–Weinberg principle wikipedia , lookup
X-inactivation wikipedia , lookup
Genome (book) wikipedia , lookup
Designer baby wikipedia , lookup
Microevolution wikipedia , lookup
Do Now: True or False? 1. Certain acquired characteristics, such as mechanical or mathematical skill may be inherited. 2. Color blindness is more common in males than in females 3. A person may transmit characteristics to offspring which he/she does not show. 4. Certain inherited traits may be altered by the stars, planets or moon early in development. 5. The total number of male births exceeds female births each year. 6. There is such a thing called “Werewolf syndrome” that could be linked to genes. Hypertrichosis (“werewolf syndrome”) Stephen Bibrowski as “Lionel the Lion-faced Man” Patterns of Heredity Genetics Chapter 4 Objectives: To distinguish between heredity and inheritance To describe Mendel’s experiments in heredity To compare heterozygous vs. homozygous and dominant vs. recessive. Genetics = the study of heredity by which traits are passed from parents to offspring The passing of genes/traits from parents to offspring. Many of your traits, including eye color, shape of your eyes, texture of your hair, height, weight, resemble those of you parents! Inheritance -passing of traits by heredity segment of DNA on a chromosome that codes for a particular protein genes occur in pairs Thanks Mom and Dad! We inherit genes from our parents Those genes code for the traits we express Most traits are coded by more than 1 gene! Recall…. A pair of chromosomes are called homologous (homo meaning same) Homologous chromosomes have the same size, structure, and genetic information. What are alleles? Alternative forms of a gene. Dominant capital letter (shields recessive trait) Recessive Lowercase letter (usually hidden) T = tall t = short Do Now What is genetics? What are alleles? Provide examples! Who is the father of genetics!? The history of Gregor Mendel- 1866 Austrian Monk – Czech Father of Genetics! Bred different varieties of garden pea plants. First to develop rules that accurately predict patterns of heredity. • Discovered how traits were inherited in a population – transfer of pollen from anthers to stigma in flowers 1) self pollination occurs within the same flower or same plant 2) cross pollination occurs between different plants 1. Several traits exist in two clear different forms. Ex: Flower color was either purple OR white 2. The male and female reproductive parts are enclosed within the same flower. It is easy to control mating by allowing a flower to fertilize itself (self fertilization), or you can transfer pollen to another flower (cross pollination). 3. The garden peas are: - Small - Grow easily - Mature quickly - Produce many offspring. **Results can be obtained quickly with many offspring. Steps in Mendel’s research… 1. Allowed each garden pea to self-pollinate for several generations to ensure “true-breeding” for that particular trait. P Generation = parental generation 2. Mendel then cross-pollinated two P generation plants that had different forms of the trait (purple and white flower). The offspring from that were called the F1 generation. F1 generation- Filial Generation 3. Allowed the F1 generation to self-pollinate and those offspring are called the F2 generation. F2 Generation - Filial Generation Mendel’s Crosses with Pea Plants P1 parental generation Pure tall plants X Cross F1 first filial generation F Pollination All Tall plants Self second filial 2 generation Pure short plants Pollination 787 tall plants, 277 short plants 3 to 1 ratio Mendel’s 3 Laws of Inheritance 1. Law of Dominance-Each trait is controlled by 2 factors, one factor (dominant ) may mask the other factor (recessive ) preventing it from having an effect. Mendel’s 3 Laws of Inheritance 2. Law of Segregation-Each allele a person has separates into different gametes Ex. Ww – one W goes in one sperm and the other w goes into another sperm Ww W w Mendel’s 3 Laws of Inheritance 3. Law of Independent Assortment- Gene pairs (homologous) will separate randomly into gametes (metaphase I of meiosis) (Why? Random orientation of homologous pairs at the metaphase plate) Mendel Video https://www.youtube.com/watch?v=GTiO ETaZg4w Phenotype vs. Genotype Genotype: Genetic makeup of an organism (genes). (internal information. Ex: BB, Bb, bb) Phenotype: the physical characteristics of an organism. (Ex. Blue Eyes, or Brown Eyes) Example of Genotype and Phenotype TT genotype Tall phenotype Homozygous – when both alleles of a pair are the same homozygous dominant homozygous recessive TT tt Heterozygous – when both alleles of a pair are not the same heterozygous (tall) Tt Recessive: Need two recessive alleles in order to express it. (bb) Dominant: The expressed form of the trait when present (even if it is just 1 allele) (Bb or BB) In dogs, black fur is dominant over white fur color. B = black fur b = white fur BB or Bb bb If Joseph Gordon-Levitt is heterozygous for black hair… (H=Black, h=blonde) 1. What is JGL’s genotype? 2. What is JGL’s phenotype? Beyonce is BB. (B= brown eyes, b=blue eyes) 1. What is her genotype? 2. What is her phenotype? 3. Is her heterozygous or homozygous? Explain. Punnett Square A diagram that predicts the outcome of a genetic cross by considering all possible combinations of gametes in the cross. Probability calculations can predict the results of genetic crosses. It is the likelihood that a specific event will occur. = number of one kind of possible outcome Total number of all possible outcomes Example: If you flip a coin, you will have 1 outcome, but two possible outcomes. Your answer would be ½. Question 1 A jar contains 3 red marbles, 7 green marbles, and 10 white marbles. If a marble is drawn at random, what is the probability that this marble is white? Question 2 Suppose you toss a coin and roll a dice. What is the probability that you toss heads and roll a four? Question 3 Two dice are rolled, find the probability that the sum is equal to 5. When flipping a coin and it lands on tails ½ or 1:2 Genotypic ratio: What is genetically written Phenotypic ratio: what physical traits you would see 3:1 3 Black : 1 White Assign symbols 2. Determine parents genotype 3. Draw punnett square 4. Place gametes on left + top of square 5. Fill in punnett square 6. Analyze + answer questions 1. T: Tall plants t: Short plants 1. 2. Phenotypic Ratio and %: Genotypic Ratio : Monohybrid Cross R= Can roll your tongue r= Can’t roll your tongue R Genotype Ratio: Phenotype Ratio: R r r Lets Try a Monohybrid together! 1) Daffy Duck is heterozygous for black feathers. Daisy Duck is homozygous for yellow feathers. Set up a punnett square and determine probabilities of their potential offspring. (Both genotype and phenotype ratios!) 2) B = Black b = yellow Do Now Sleeping Beauty has freckles. Her prince charming is heterozygous for no freckles. What are the chances of her children having freckles? Please show your work. Test cross – an individual with unknown genotype is crossed with a homozygous recessive individual Used to determine the genotype of any individual whose phenotype is dominant Ex: A yellow pea is yellow, but can be YY or Yy. To find out if the yellow pea is homozygous or heterozygous, you cross it with a recessive pea and the outcome will tell you depending on the ratio. Lets Try a Test Cross Spongebob squarepants doesn’t know whether or not he is Homozygous Dominant or Heterozygous for his yellow color. The recessive trait is a white sponge. Let’s say that we perform a “test cross” on spongebob (spongebob + a white female sponge) and all of the baby sponges are yellow. What would spongebob’s genotype be? And Another… In fruit flies, red eyes are dominant over sepia eyes. While working in your lab late one night, a red eyed fruit fly came in for a crash landing on your apple. Wanting to know more about your new friend, you decide to run a test cross on your little buddy. If all of the offspring turn out to be red-eyed ( all 347 of them!!) what would be the genotypes of the flies used in your test cross? (Use R and r) __________x __________ Genotypic Ratio: Phenotypic Ratio: Just one more…. You are a mink farmer. In minks, black fur is dominant over white fur. The market for black mink fur cots is higher than white fur. You decide only to raise black mink. However, the guy you bought your minks from seems a little strange. You want to make sure these minks are true breeds so you run a test cross. Give the phenotypes of the minks in your test cross: ○ _________x________ In the first run, 30 out of 60 offspring are black, and the test are white! What are the actual genotypes of the minks in your test cross? ○ ________x_________ Was the black furred mink a pure breed? What is his genotype? What is a dihybrid Cross? A dihybrid cross allows us to predict possible outcomes of offspring that will have 2 traits simultaneously. Ex: what would you get if you crossed a Brown-haired brown-eyed male with a blonde-haired blue-eyed female? How many of the children would have brown hair and brown eyes? Brown hair and blue eyes? Blonde hair and brown eyes? Blonde hair and blue eyes? Example Setting up Dihybrid Crosses 1. Determine parent genotypes 2. Determine alleles to be passed down 3. Set up punnet square 4. Determine outcome Phenotype Ratio Genotype Ratio Dihybrid Crosses Looking at two different traits Ex. Hair color and eye color B=brown eyes b=blue eyes R=Brown hair r=blonde hair Mother is heterozygous for both traits Father is heterozygous for eye color and homozygous dominant for hair color What could the phenotypes and genotypes be of their children? More Practice Mickey Mouse is heterozygous for Round ears and homozygous for Black eyes. Minnie Mouse also is homozygous for Floppy ears and heterozygous for Black eyes. Determine genotype and phenotype ratios. (B=black, b=brown, R=round, r= floppy.) 10.3 Gene Linkage and Polyploidy Several genes on a chromosome Gene Linkage: When two genes are close to each other on the same chromosome Gene Linkage Linked genes on a chromosome results in an exception to Mendel’s law of independent assortment Linked genes usually do not segregate because they are so close together on a chromosome. Drosophila (Fruit Flies) First organism with linked genes Linked genes typically travel together during crossing over Chromosome Map Crossing over occurs more frequently between genes that are far apart Map of genes on a chromosomes and frequency of crossing over Polyploidy Occurrence of one or more extra sets of all chromosomes in an organism. Ex. A triploid organism (3n) - means that it has three complete sets of chromosomes. True or False – Correct false statements _______ 1. Crossing over occurs more frequently between genes that are close together on a chromosome. _______ 2. Gene linkage was first studied by using garden peas. _______ 3. Scientists call a drawing like the one shown below a chromosome map. _______ 4. Chromosome map percentages represent actual chromosome distances. Inheritance of Traits Pedigree – a family history that shows how a trait is inherited over several generations. You can see how a genetic disorder runs in a family. Carriers are individuals who are heterozygous for an inherited disorder but do not show symptoms. Carriers can pass the allele for the disorder to their offspring DO NOW Fill in the genotypes for the following pedigree B=brown eyes b = blue eyes Do Now Please hand in your labs in the bin up front. Then answer: What do you think incomplete dominance means? 11.2 Incomplete Dominance: Heterozygous phenotype is an intermediate phenotype between the two homozygous phenotypes. Two alleles are blended Ex) Four O’clock Flowers Red + White = Pink Incomplete Dominance Lets Practice! In snapdragons, flower color is controlled by incomplete dominance. The allele for Red is R and the allele for white is W. 1. Knowing this trait is incompletely dominant, what would be the phenotype for the heterozygous condition (RW)?_______________ 2. For each phenotype below: Identify the genotype. Red____________ White ____________ A pink flowered snap dragon is crossed with a white flowered snapdragon. Make a Punnett Square and: 1. Give the expected probabilities for each genotype and phenotype 2. Give the ratios for the genotypes and phenotypes. Codominance Neither trait is dominant instead, both traits are expressed (No Blending) Ex) Roan Cows. white hair (HW) is codominant with red hair (HR) horses with genotype (HRHW) have coats with a mixture of red and white hairs (roan) Sickle Cell Disease Affects red blood cells and ability to transport oxygen. Homozygous recessive alleles= Heterozygous= Homozygous dominant alleles= Sickle Cell and Malaria People who are heterozygous for sickle cell, have a higher resistance to malaria. Multiple alleles – 3 or more alleles that control a trait Example – blood type (IA,IB,io) GENOTYPES IAIA IAio RESULTING PHENOTYPES Type A Type A I BI B IBio Type B Type B I AI B ioio Type AB Type O Universal Donor? Sample Problem Determine the possible offspring of the following crosses 1. AB and O 2. AA and BO 3. AB and AB More Practice A father is heterozygous for his type B blood and the mother has type O blood. What are the possible blood types of the babies born from this couple? Just one More….. A father is heterozygous for his type A blood and his mother is heterozygous for her type B blood. What percentages of their offspring would you expect to have…. Type A Blood______% Type B Blood______% Type AB Blood______% Type O Blood______% Coat Color of Rabbits Rabbits have a hierarchy of coat color 4 alleles (C, cch, ch, and c) Dominant C > cch> ch > c Recessive C Full color cch Chinchilla ch Himalayan c albino Coat Color of Rabbits Chinchilla Albino Full Color Himalayan Let’s try a sample problem cc x Ccch Genotype and phenotype ratios Do Now- What do you see? What do you see? http://enchroma.com/test/instructions/ Autosomal vs. Sex-Linked Autosomal – it will appear in both sexes equally trait whose allele is located on the X or Y chromosome. Most are recessive. X linked: gene is located on the X chromosomes Y linked: gene is located on the Y chromosome Because males carry only one X chromosome, a male who carries a recessive allele on the X or Y will exhibit the sex linked condition. A female who carries a recessive allele on one X chromosome will not exhibit the condition if there is a dominant allele on her other X chromosome. Needs 2 recessive X to show condition! What are the chances of having a girl? How would you go about solving it? Sex Chromosomes We have 23 pairs of chromosomes 1 pair are known as the sex chromosomes, which determines the sex of the offspring Males = XY Females = XX Sex-Linked Traits A man who is color blind marries a woman that is heterozygous for color blindness. What is the chance of having a color blind boy? Polygenic Traits – Interaction of multiple pairs of genes A wide range of variability! Genes can be located on different chromosomes Traits can be influenced by the environment! Hydranga Flowers: When in acidic soil, they bloom blue flowers When in basic soil, they will bloom pink flowers Arctic Fox – Enzymes will make pigments during a certain time of the year. Treating Genetic Disorders Most genetic disorders cannot be cured, although progress is being made. Families who have a history of genetic disorders are recommended to undergo counseling before having a child. They can find out how it could affect their offspring. Some genetic disorders can be treated if diagnosed early enough, such as PKU (lacking a certain enzyme). If known, that child can be put on a certain diet and medicine routine. Treating Genetic Disorders Most genetic disorders cannot be cured, although progress is being made. Families who have a history of genetic disorders are recommended to undergo counseling before having a child. They can find out how it could affect their offspring. Some genetic disorders can be treated if diagnosed early enough, such as PKU (lacking a certain enzyme). If known, that child can be put on a certain diet and medicine routine. What is genetic mapping? Genetic mapping - also called linkage mapping can offer firm evidence that a disease transmitted from parent to child is linked to one or more genes. It also provides clues about which chromosome contains the gene and precisely where it lies on that chromosome. Genetic maps have been used successfully to find the single gene responsible for relatively rare inherited disorders, like cystic fibrosis and muscular dystrophy. Maps have also become useful in guiding scientists to the many genes that are believed to interact to bring about more common disorders, such as asthma, heart disease, diabetes, cancer and psychiatric conditions. Gene Therapy May soon allow scientists to correct certain recessive genetic disorders by replacing defective genes with copies of a healthy one. First step of gene therapy is to isolate a copy of the gene. Scientists are trying to input that gene into the cell by attaching it to a cold virus. Attempts in humans have not been successful. However, the outlook is promising. Genetic Disorders Sickle Cell Anemia Cystic Fibrosis (CF) Hemophilia Tay- Sachs Disease Huntington’s Disease (HD) Hypercholesterolemia In Groups, you will research a specific disease and present it to the class. TWINS