Welcome AP Super-teachers!Mendelian GeneticsNovember 3, 2011

Chapter 14 (in Campbell)Mendelian Genetics

The Father of Genetics & Cook for the Abbey

Chapter 14Objective 1TSW: Recognize the differences/similarities between the terms: Trait, Character, allele, gene

Character and Trait

Fig: 14.4

One from EACH parentSperm AND Egg

Chapter 14Objective 2TSW: Recognize and explain the differences and source between the following terms: phenotype and genotype; truebreed and hybrid

Phenotype vs. GenotypePhysical Trait vs. Gene allele type

Chapter 14Objective 3TSW: Understand and apply Mendels laws of Segregation and Independent assortment

Teach the SkillMendels Law of Segregation (Segregate means to separate)The genes ON chromosomes can move independently of one another. This is supported by what happens during Crossover of Prophase I.

Teach the SkillMendels Law of Independent ASSORTMENT (This basically states that VARIATIONS are possible on chromosomes.) ( Assortment means variety exists) This states that chromosomes move independently of one another. This occurs at Anaphase I and II in Meiosis. It also occurs in Anaphase of Mitosis too.

Chapter 14Objective 4TSW: Be able to calculate probability in genetic problems using the rule of multiplication.Be able to relate these problems to punnett squares of genotypes.

Probability worksheet*

EXAMPLE: What is the probability that the following parents will produce the indicated (DESIRED) offspring? Assume Independent Assortment of all gene pairs.Parents Genotypes: Male: AABb CC X Mother: Aa Bb ccOffspring (Desired) Genotype: AABbCc

How to work quicklyl lMALE:A A l B b l C C l X l X FEMALE:A a l B b l c cl lOFFSPRING: A A l B b l C c(DESIRED)l l# of Arrows: 2l 2 l 4 l lFraction: 1/2 x 1/2 x 1 = 1/4 Probability OR 25% Chance for that DESIRED genotype outcome

Chapter 14Objective 5TSW: Work with, relate phenotypic ratio outcomes, and Mendels laws associated with Punnett Squares.

LE 14-7Dominant phenotype,unknown genotype:PP or Pp?If PP,then all offspringpurple:ppPPPpPpPpPpIf Pp,then 1 2 offspring purpleand 1 2 offspring white:ppPPppppPpPpRecessive phenotype,known genotype:pp

Fig: 14.8 (Dihybrid)

Chapter 14 - Objective 6Teach the SkillTSW: Differentiate and give specific examples related to the following terms: Co.mplete Dominance, Incomplete Dominance, and Codominance

CompleteTeach the Skill

IncompleteTeach the Skill

CodominanceTeach the Skill & Cell Signaling tie-in

Chapter 14 Objective 7TSW: Understand, give specific examples, and relate to Punnett Squares with the concept of Multiple Alleles

Multiple AllelesTeach the Skill & Cell Signaling tie-in

Chapter 14 Objective 8TSW: Understand and give examples of the following terms: Pleiotropy, Epistasis, Polygenic Inheritance, and Multifactorial

Teach the Skill & Tie into Protein Synthesis and Protein StructurePleiotropyThis is where one gene affects multiple Phenotypes. ( Pleio means multiple)Sickle Cell Disease is a great example. (This gene AFFECTS the red blood cells Shape, Oxygen carrying ability, Malaria resistance, etc.) The one gene is affecting multiple phenotypes.

Pleiotropy (Sickle Cell)

Teach the SkillEpistasis (Fig: 14.11)A gene at one locus affects a gene at a second locus.Hair is a great example. (Several genes are interacting to create hairs phenotypes These are: color, shape, thickness, texture, etc.) (epi means source; stasis means location) The source is affecting another location.Gets a 9:3:4 ratio This is key.

LE 14-11SpermBCbCBcbcBbCcBBCcBbCCBBCCBbCCbbCCBbCcbbCcBbccBBccBbCcBBCcBbCcbbCcBbccbbccBCbCBcbcBbCcBbCc1414141414141414916316416

Teach the SkillPolygenic Inheritance (Fig: 14.12)This is where there exist many different degrees of phenotypic outcomes.This is due to Quantitative Characters. (Quantity -how many alleles did you receive from your parents.)poly means many; genie refers to genes; inheritance from your parentsSkin Color is a great example. (We have many different degrees of skin pigmentation ranging from Albino Black, Black. It depends on how many copies of the same gene for making the skin pigment melanin you inherited from your parents in the sperm and egg.)Norm of the Reaction This refers to where the majority of organisms fall on the bell curve for that trait.Evolution? The norm can tell you about the type of environment organisms live in. The norm is because some trait is beneficial in that environment.

LE 14-12aabbccAabbccAaBbccAaBbCcAABbCcAABBCcAABBCCAaBbCcAaBbCc20/6415/646/641/64Fraction of progeny

Teach the Skill & Tie back into EcologyMultifactorial (Fig: 14.13)Many ENVIRONMENTAL factors are affecting the phenotypic display of genes in that organism.This gives fuel to the argument over Nature vs. Nurture in organisms. (The genetics vs. the environment.)While there are equally legitimate arguments for both sides. The overwhelming evidence supports a 50/50 reality. 50% of our behavior is innate (in our genetics); after all who teaches a dog to bark. The other 50% comes from our experiences or living environment; such as eating good foods affects the body you create over time.Height, intelligence, and weight can all be considered multifactorial.

Multifactorial example(Acid in soil changes the color)

Chapter 14Objective 9TSW: Be able to read, discuss, and convey inheritance patterns using pedigrees.

LE 14-14bFirst generation(grandparents)FfFfFF or FfffffFfFfffffFfSecond generation(parents plus auntsand uncles)Thirdgeneration(two sisters)Attached earlobeFree earlobeffFForFfRecessive trait (attached earlobe)

LE 14-14aWwwwwwWwWwwwWwwwwwWwWWwworWwNo widows peakThirdgeneration(two sisters)Widows peakSecond generation(parents plus auntsand uncles)First generation(grandparents)Dominant trait (widows peak)

Pedigree of Color Blindness

Pedigree 3males = squarefemales = circle1/2 Shaded = unaffected carriershaded = affectedClaim (PoI) = Reason = How do maternal patterns of inheritance relate to mitochondria?

Chapter 14Objective 10TSW: Explain the inheritance of recessive and dominant disorders.

Human Recessive Disorders

Cystic Fibrosis (Also referred to as CF.)This is the most common lethal genetic disease.This disorder affects 1 in 2,500 births.In Caucasians, 1 in 25 people is a carrier for the disorder.The disorder creates a faulty Chloride ion (Cl-) protein carrier on cell membranes in the lungs. This causes fluid (water0 to build up in the lung tissues. People drown in their own fluid.They are also prone to get multiple infections in the lungs.Treatment? Since it is genetic there is NO cure. Patients have to get the fluid drained from the lungs periodically for their ENTIRE life. There are medicines to help reduce the number of times this has to occur.

RecessiveTay-Sachs DiseaseThis disorder creates a non-functional lysosome in brain cells. Brain cells need massive amounts of energy to function properly; therefore, they feed upon lipids primarily. The lysomomes break them down using beta oxidation for use in cellular respiration. The lysosomes associated with this disorder are missing an enzyme to be able to do this; so they just fill up with lipids. The cells fill with lipids and then die.This disorder mainly affects the Jewish Culture because of marrying within the culture. The Jewish culture has a high percentage of carriers.The children affected, usually die a painful, blind death by age 5.

Recessive (BE CAREFUL IN DISCUSSING)Sickle-cell Disease (Fig: 5.21 Pg. 84)This disorder is the most common genetic disorder within the black population. Other populations can get it too. It is not exclusive.It affects 1 in 400 births.The 6th Amino Acid is changed (Glutein Valine) in the PRIMARY sequence of one of the proteins needed to make red blood cells. (The easy way to remember this is: 666 is the number of the beast. 6 is the amino acid that changed to create this horrible disease. It went from good [glutein] to very bad [valine].)Sickle- cell trait (trait is used to refer to individuals that are carriers.)These individuals have resistance to Malaria because of the ONE recessive allele they possess but mainly have normal red blood cells for carrying oxygen.This is referred to as the Heterozygous Advantage. They have an advantage over individuals that are homozygous dominant or homozygous recessive. Homozygous dominant are NOT resistant to Malaria. Homozygous recessive are also resistant to Malaria; BUT they have the disease to contend with.Sickle cell identification of carriers in individuals is important to avoid this disorder from occurring.These sickle shaped cells have reduced oxygen carrying ability. They also are painful when the points of the cell jab into the walls of the blood vessels.Treatment? There is no cure as it is genetic. Some medicines help with the pain or low oxygen levels.

Dominant Human DisordersAchondroplasia (Fig: 14.15) (This is referred to as Genetic Dwarfism.)This disorder affects 1 in 10,000 births.Most people are homozygous recessive and there for much taller than these individuals.

Dominant(BE CAREFUL IN DISCUSSING)Huntingdons DiseaseThis disorder affects 1 in 10,000 births.It has a late life onset usually in the 40-50 age range. (Usually AFTER children are born.)The dominate gene has a locus on tip of Autosome 4.Family history is important in diagnosis of this disorder. (Pedigree can help.)It is a slow degenerative disorder affecting the brain that is almost always fatal.

Chapter 15 (in Campbell)Chromosomal Inheritance

Chapter 15Objective 1TSW: Be able to understand the difference between the terms: wild type and mutant type.

Wild type (red) vs. Mutant type (white)

Chapter 15Objective 2TSW: Understand and relate to a pedigree, to incude occurrence rates, the difference between the terms: linked genes and sex-linked genes.

Autosomes and linked genes

Sex-Linked MaleTeach the Skill

Most common on the AP examColor BlindnessThis is the result of a faulty gene (recessive) on the X chromosome for making a particular type of color absorbing protein in cones of the retina of the eye.The most common type is Red/Green Colorblindness. (Red and Green appear gray.)

twoDuchenne Muscular Dystrophy (atrophy means break down)This affects about 1 in 3,500 male births.These individuals cannot make the muscle protein Dystrophin. (Thus the name DYStrophy)This disorder is a slow weakening of the muscles until around age 20. They then become confined to a wheelchair until death soon after.

ThreeHemophilia (Means love of bleeding)These individuals cannot make Anti-hemolytic Factor. (AHF for short.)They experience problems with bleeding to death.This was a disorder associated with the Royal Blue-Bloods of Europe They were inbreeding to keep the crown In the Family.Treatment? These individuals have to keep AHF with them at all times in case they get hurt. If they do get hurt and start to bleed they will require a shot of AHF to stop the bleeding. Even a bruise (bleeding under the skin) can possibly lead to death.

Chapter 15Objective 3TSW: Be able to construct a linkage map using crossover frequency.

Linkage Map ConstructionHe used crossover rates to determine the loci on chromosomes. (Fig: 15.7)The finished product is called a Linkage Map. (Fig. 15.8)The smaller the rate; the closer they are to each other on the same chromosome.The higher the rate; the farther apart they are from each other on the same chromosome.The loci are measured in Centimorgans or map units.

LE 15-7Recombinationfrequencies9%9.5%17%bcnvgChromosome

Chapter 15Objective 4TSW: Explain and relate the terms: X inactivation and mosiacism.

Teach the SkillX Inactivation (Turning off one of the X chromosomes.)This ONLY occurs in females because females have two Xs (Males only have one and it MUST remain active.)A Barr body is formed (From condensing one of the X chromosomes) to inactivate one set of information.The Barr body will be located on the nuclear envelope. (Criminal Forensics? This is how they can tell the sex of the suspect. Males do not have them on their nuclear envelope.)Mosaicism (Fig: 15.11) (A Mosaic is a puzzle.)In humans, it is called Complex Skin. (Dry spots from moms X chromosome mixed with Sweaty Greasy spots from dads X chromosome.)Facial products is a Billion Dollar Industry as it only affects females, who tend to be VERY concerned with their facial appearance and types of makeup that Work on their skin type.

Barr Body

Fig: 15.11

Chapter 15Objective 5TSW: Differentiate between, identify, and recognize terms associated with the following abnormalities: Chromosomal Number and Chromosomal Structure.

NumberWHEN IS IMPORTANT & Teach the Skill

Structure & Teach the Skill

Chapter 15Objective 6TSW: Understand and relate the importance of genomic imprinting.

UniquenessGenomic ImprintingEssentially, this is Erasing your PARENTS unique information to create YOUR own unique information.Erasing genetic information is accomplished by heavy Methylation.Attaching large amounts of methyl (CH4 molecules) to the DNA.This acts like a jacket covering up the underlying genes.The amount varies for each cell that undergoes meiosis.If very little occurs the offspring have a strong resemblance to the parents.If a lot occurs the offspring have very little resemblance to the parents.

Chapter 15Objective 7TSW: Understand and relate the importance of extra-nuclear DNA.

Extranuclear DNA(This DNA CAN can affect an organism)

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