InheritanceInheritanceConceptual BiologyConceptual Biology

Chapter 5.1 - 5.2Chapter 5.1 - 5.2

VocabularyVocabulary1.1. geneticsgenetics

2.2. heredityheredity

3.3. self-fertilizeself-fertilize

4.4. traittrait

5.5. genegene

6.6. alleleallele

7.7. hybridhybrid

8.8. dominantdominant

9.9. recessiverecessive

10.10. segregationsegregation

11.11. probabilityprobability

12.12. Punnett square Punnett square

13.13. homozygoushomozygous

14.14. heterozygousheterozygous

15.15. phenotypephenotype

16.16. genotypegenotype17.17. multiple allelesmultiple alleles18.18. polygenic traitspolygenic traits19.19. gene linkagegene linkage20.20. gene mapgene map

II. Mendel & Genetics. Mendel & GeneticsA.A. How do How do

characteristics pass characteristics pass from parents to from parents to offspring?offspring?1.1. heredityheredity = how = how

characteristics are characteristics are passed from parent passed from parent to offspringto offspring

2.2. geneticsgenetics = scientific = scientific study of hereditystudy of heredity

B.B. Gregor Mendel – father Gregor Mendel – father of geneticsof genetics

1.1. Mendel worked with pea Mendel worked with pea plants that self-fertilize.plants that self-fertilize.

a.a. self-fertilize self-fertilize = sperm = sperm and egg from the and egg from the same plant that go same plant that go through fertilizationthrough fertilization

b.b. self-fertilizing plants self-fertilizing plants produce offspring produce offspring identical to identical to themselvesthemselves

2.2. Mendel decided to cross-Mendel decided to cross-fertilize these peas and fertilize these peas and study the resultsstudy the results

C. Genes and DominanceC. Genes and Dominance1.1. genegene = section of DNA that has instructions for making a protein, each protein = section of DNA that has instructions for making a protein, each protein

causes a characteristiccauses a characteristic

2.2. traittrait = a specific characteristic, ex: seed color or plant height = a specific characteristic, ex: seed color or plant height3.3. Mendel studied pea plants that had different traits, ex: green or yellow seedsMendel studied pea plants that had different traits, ex: green or yellow seedsDRAWDRAW

Seed Shape

Flower Position

Seed CoatColor

Seed Color

Pod Color

Plant Height

PodShape

Round

Wrinkled

Round

Yellow

Green

Gray

White

Smooth

Constricted

Green

Yellow

Axial

Terminal

Tall

Short

Yellow Gray Smooth Green Axial Tall

4.4. Mendel learned some forms of Mendel learned some forms of genes are dominant and others genes are dominant and others are recessive.are recessive.

a.a. dominantdominant = trait that covers up = trait that covers up another traitanother trait

b.b. recessiverecessive = trait that is covered = trait that is covered over and seems to disappearover and seems to disappear

c.c. allelesalleles = different forms of a = different forms of a gene that can be dominant or gene that can be dominant or recessive, ex: tall and shortrecessive, ex: tall and short

P Generation F1 Generation F2 Generation

Tall Short Tall TallTall Tall Tall Short

DRAW - MendelDRAW - Mendel’’s Pea Experiments Pea Experiment

Gene Location and DominanceGene Location and Dominance Genes are parts of Genes are parts of

DNA that code for one DNA that code for one protein.protein.

Genes have two forms Genes have two forms called alleles.called alleles.

Alleles can be Alleles can be dominant or recessive.dominant or recessive.

Use a capital letter for Use a capital letter for the dominant allele, the dominant allele, lower case for lower case for recessive allele.recessive allele.

D.D. SegregationSegregation1.1. Mendel crossed a tall plant with a short Mendel crossed a tall plant with a short

plant to make plant children.plant to make plant children.a.a. All the children were all tall. He called All the children were all tall. He called

these plants hybridsthese plants hybrids

b.b. hybridhybrid = offspring of parents with = offspring of parents with different traitsdifferent traits

2.2. Mendel crossed the plant children with Mendel crossed the plant children with themselves to make plant themselves to make plant grandchildrengrandchildren

a.a. The grandchildren were 3:1, tall to short The grandchildren were 3:1, tall to short plants!plants!

b.b. The short trait came back ¼ of the time (in The short trait came back ¼ of the time (in 1 out of 4 plants)1 out of 4 plants)

3.3. Alleles for a trait separate when sex cells Alleles for a trait separate when sex cells are madeare madea.a. Each sex cell carries one copy of each gene Each sex cell carries one copy of each gene

as an alleleas an allele

DRAW Figure 2 in Chapter 5

ChildrenChildren

GrandchildrenGrandchildren

concluded that

which is called

which is called

GregorMendel

Dominance Segregation

Peaplants

Genesdetermine

traits

Some alleles are dominant,

and some alleles are recessive

Alleles are separated when making sex cells

experimented with

E. Gregor Mendel graphic organizerE. Gregor Mendel graphic organizer

Although Mendel did most of his

genetics work on pea plants, his ideas about

genetics also apply to all

other organisms…

Probability PracticeProbability Practice If you toss a coin, what is the probability If you toss a coin, what is the probability

of getting heads? Tails? of getting heads? Tails? 1 chance in 2. This is ½ or 50%.1 chance in 2. This is ½ or 50%.

If you toss a coin 10 times, how many If you toss a coin 10 times, how many heads and how many tails would you heads and how many tails would you expect to get? expect to get? 5 heads and 5 tails = ½ of the time 5 heads and 5 tails = ½ of the time

heads or tailsheads or tails Working with a partner, have one Working with a partner, have one

person toss a coin ten times while the person toss a coin ten times while the other person tallies the results on a other person tallies the results on a sheet of paper. Then, switch tasks to sheet of paper. Then, switch tasks to produce a separate tally of the second produce a separate tally of the second set of 10 tosses.set of 10 tosses.

IIII. . Probability and Punnett SquaresProbability and Punnett SquaresA.A. Genetics & ProbabilityGenetics & Probability

1.1. ProbabilityProbability = the chance that a = the chance that a particular event will happenparticular event will happen

2.2. Probability is used to predict the traits Probability is used to predict the traits of offspringof offspring

B.B. Punnett squaresPunnett squares1.1. Punnett squarePunnett square = a tool used to predict = a tool used to predict

the traits in offspringthe traits in offspring2.2. HomozygousHomozygous = organisms that have = organisms that have

two identical alleles for a trait (TT or two identical alleles for a trait (TT or tt)tt)

3.3. Heterozygous Heterozygous = organisms that have = organisms that have two different alleles for a trait (Tt)two different alleles for a trait (Tt)

4.4. PhenotypePhenotype = physical characteristics (ex: tall or = physical characteristics (ex: tall or yellow)yellow)

5.5. GenotypeGenotype = genetic makeup, alleles (ex: Tt or tt) = genetic makeup, alleles (ex: Tt or tt)

DRAWDRAWPunnett square Punnett square (for only one trait)(for only one trait)

C.C. Probabilities Predict AveragesProbabilities Predict Averages1.1. Probability does not predict exact Probability does not predict exact

outcomesoutcomes

2.2. larger # of events larger # of events more accurate the more accurate the probabilityprobability

3.3. larger # of offspring larger # of offspring closer the resulting closer the resulting offspring will be to what was predictedoffspring will be to what was predicted

4.4. Ex: When we breed two fruit flies and get Ex: When we breed two fruit flies and get thousands of offspring, the babiesthousands of offspring, the babies’’ characteristics are very close to our characteristics are very close to our prediction. If you breed horses and only prediction. If you breed horses and only get two offspring, their characteristics may get two offspring, their characteristics may not match the prediction because there are not match the prediction because there are too few offspring.too few offspring.

A.A. Beyond Dominant & Recessive AllelesBeyond Dominant & Recessive Alleles1.1. Some alleles are neither dominant or recessiveSome alleles are neither dominant or recessive

2.2. Incomplete DominanceIncomplete Dominance - heterozygous phenotype - heterozygous phenotype somewhere in between the two homozygous phenotypessomewhere in between the two homozygous phenotypes

a.a. ex: snapdragon flowers ex: snapdragon flowers

b.b. use two different letters for the alleles when doing a Punnett use two different letters for the alleles when doing a Punnett squaresquare

Incomplete Incomplete DominanceDominance

IIIIII. Advanced Genetics. Advanced Genetics

DRAWDRAW

3.3. CodominanceCodominance - both alleles - both alleles contribute to the phenotype contribute to the phenotype separatelyseparately

a.a. ex: Appaloosa horsesex: Appaloosa horses

b.b. use two different letters for the alleles use two different letters for the alleles in a Punnett squarein a Punnett square

CodominanceCodominance

4.4. Multiple AllelesMultiple Alleles - more than two - more than two alleles for a gene existing in a populationalleles for a gene existing in a population

a.a. ex: rabbit coat colorex: rabbit coat color1)1) alleles for where & how much color alleles for where & how much color

expressed: C, cexpressed: C, cchch, c, chh, c, cb.b. ex: human blood typeex: human blood type

1)1) alleles: alleles: A, B, and OA, B, and O

Human BloodHuman Blood

Rabbit Coat Color AllelesRabbit Coat Color Alleles

5.5. Polygenic traitsPolygenic traits - traits controlled by two - traits controlled by two or more genesor more genes

a.a. ex: skin color in humans is controlled by ex: skin color in humans is controlled by 4 different genes4 different genes

b.b. there are many genes for human eye there are many genes for human eye color, 2 we know well: 1 for a brown and color, 2 we know well: 1 for a brown and 1 for a green pigment, ex: BbGg1 for a green pigment, ex: BbGg

Polygenic Trait Polygenic Trait - Eye Color, 2 - Eye Color, 2 different genesdifferent genes

Predicting Your ChildrenPredicting Your Children’’s Eye Color: s Eye Color: http://genetics.thetech.org/online-exhibits/what-color-eyes-will-your-children-have

Location on chromosomes Chromosome # 2

IVIV. Gene Linkage and Mapping. Gene Linkage and MappingA.A. Gene LinkingGene Linking

1.1. Some genes seem to be Some genes seem to be ““linkedlinked”” since they are often inherited since they are often inherited togethertogether

2.2. These genes are located close These genes are located close together on the same chromosometogether on the same chromosome

B.B. Gene MapsGene Maps1.1. Gene maps show the location of Gene maps show the location of

genes on a particular chromosomegenes on a particular chromosome