blue people of troublesome creek

Blue People of Troublesome Creek

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• 1820 - French orphan Martin Fugate settled in Troublesome Creek

• Married Elizabeth Smith - 7 children of whom 4 reported to be ‘blue’

• Many consanguineous marriages (normally cousin - cousin)

• One of their sons married an aunt

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• 6 generations later Ben Stacy born (1975)• Ben’s skin blue - no apparent cause• (1998) lips and fingernails still blue when

stressed• What is the cause? Treatment?• Madison Cawein (1960 ) proposed answers

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Mendelian Genetics

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Genetics Facts & Fallacies Quiz

1. Certain acquired characteristics, such as mechanical or mathematical skill, may be inherited.

2. Identical twins are always of the same sex.

TRUE

TRUE6



3. Fraternal twins are more closely related to each other than to other children in a family.

4. The father determines the sex of a child.

FALSETRUE

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3. Fraternal twins are more closely related to each other than to other children in a family.

4. The father determines the sex of a child.

TRUE

TRUE8



5. Each parent contributes half of a child’s genetic make up.

6. Certain drugs or alcohol can cause birth defects in a fetus.

TRUE

TRUE9



7. Colorblindness is more common in males than in females.

8. A person may transmit characteristics to offspring, which he, himself does not show.

TRUE

TRUE10



9. Identical twins are more closely related than fraternal twins.

10.Certain inherited traits may be altered by the stars, moon, or planets early in development

TRUE

FALSE 11



11.Humans have 23 chromosomes.

12.The tendency to produce twins may run in families.

TRUE

FALSE

12



13.A craving for food such as strawberries may cause a birthmark on an unborn child.

14.Many of a person’s inherited traits are not apparent.

TRUE

FALSE

13



13.The parent with the stronger “will-power” will contribute more to a child’s inheritance than the other parent.

14.If a person loses a limb in an accident, it is likely that he or she will have a child with a missing limb.

FALSEFALSE 14



17.Gregor Mendel was a monk and is known as the “Father of Genetics” based on his experiments with pea plants.

18.Children born to older parents usually lack the vitality of those born to younger parents.FALS

E

TRUE

15



19.The total number of male births exceeds females births each year.

20.If a male mutt dog mates with a pedigree (show quality) female dog, all future litters of the pedigree will have some characteristics from the mutt male.

TRUE

FALSE 16


Genetic Terminology _____ - any characteristic that can be

passed from parent to offspring.

_________ - passing traits from parent to offspring

__________ - study of heredity

Trait

Heredity

Genetics

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Genetic Terminology ________ - two forms of a gene

(dominant and recessive)Alleles

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Genetic Terminology ___________ - stronger of two genes

expressed in the hybrid: represented by a capital letter (R).

___________ - gene that shows up less often in a cross; represented by a lowercase letter (r).

Dominant

Recessive

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Genetic Terminology ___________ - gene combination for a

trait (ex. RR, Rr, rr)

____________ - the physical feature resulting from ta genotype (tall, short)

Genotype

Phenotype

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Genetic Terminology _________________________ - gene

combination involving two dominant or two recessive genes (ex: RR or rr): also called _______.

_________________________ - gene combination of one dominant and one recessive allele (ex: Rr); also called ________.

Homozygous genotype

Heterozygous genotype

pure

hybrid21


Genetic Terminology __________________ - cross involving a

single trait

_______________ - cross involving two traits

Monohybrid Cross

Dihybrid Cross

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Genetic Terminology ________________

- used to solve genetics problems. (based on probability)

Punnett Square

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Fundamentals of Genetics __________ = the passing of

traits from __________ to __________.

› Transmitted by means › of information stored › in molecules of _______.

Heredityparents offspring

DNA

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Fundamentals of Genetics ___________ = scientific study of

__________Based on knowledge that traits are transmitted by ________________.

Genetics heredity

chromosomes

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Our ______________ are made up of our ________, which are pieces of ______ that code for certain ______.› For example, both of our chromosomes

might contain the genes for hair texture or height.

chromosomesgenes

Fundamentals of Genetics

DNA traits

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Fundamentals of Genetics

Humans have ____chromosomes in their somatic (body) cells.

____ chromosomes from your mom and ____ from your dad.

23

46

23

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Fundamentals of Genetics Since an organism receives

genes from _______ parents it is not exactly like either parent but like _______ parent in some ways.

both

each

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Fundamentals of Genetics ____________ = all the outside

forces that act on an organism.› Affects the development, later life,

and the expression of heredity traits of an organism.

Environment

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Fundamentals of Genetics WHAT MAKES YOU WHO YOU ARE

TODAY?› _______________________ are the two great influences, acting together all through your life.

Heredity & Environment

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Fundamentals of Genetics Genetic messages determine what

organisms ______ become.

The interaction of messages and the environment determines what organisms ______ become.

may

do

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Fundamentals of Genetics Organisms inherit

____________________, not traits!

Traits develop when genetic messages interact with the environment.

genetic message

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Gregor Mendel Gregor Mendel -

________________________ - Austrian monk

Between 1856 and 1963 his research with ________________ led to the discovery of heredity.

Did a statistical study of traits in garden peas over an eight year period.

“Father of Genetics”

garden peas

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Gregor Mendel Garden peas were a good choice for

experimentation because:1. They can be _______________________.2. They display ___________________ in one of

two contrasting forms:height – tall/shortseed color – yellow/green

3. They are normally ___________________ plants and are very easy to cross-pollinate.

cultivated quicklyseveral traits

self-pollinating

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Gregor Mendel Mendel used logical _______________

methods and kept careful __________. He used math principles of

______________ to interpret results

experimentalrecords

probability

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36


Gregor Mendel Mendel studied pea traits, each of

which had a dominant and a recessive form (_______).

The ___________ (shows up most often) gene or allele is represented with a ______________, and the _______________ with a ___________ of that same letter (ex. B, b).

allelesdominant

capital letterrecessive gene lower case

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Gregor Mendel Mendel’s traits included:a. seed shape – round (R)or wrinkled (r)b. seed color – yellow (Y) or green (y)c. pod shape – smooth (S) or wrinkled (s)d. pod color – green (G) or white (g)e. seed coat color – gray (G) or white (g)f. plant height – tall (T) or short (t)g. flower color – purple (P) or white (p)

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The different forms or types of a specific gene are called __________.› For example, a GENE for eye color might

have a blue _________, a brown _________, and a green _________.

› In plants, a gene for flower color might have a purple allele and a white allele.

alleles

allele

Mendelian Genetics Overview

alleleallele

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Because our chromosomes are in _____ sets, we have two copies of each gene, ______ from our _____ and _____ from our _____.› If both of your parents gave us the

______ ______ of gene – the same allele – then we are . . .

Because our chromosomes are in _____ sets, we have two copies of each gene, ______ from our _____ and _____ from our _____.› If both of your parents gave us the

______ ______ of gene – the same allele – then we are . . .

twoone


momone dad

sametype

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HOMOZYGOUS or pure (on both sets of our chromosomes, on both sets of genes; the allele is the ______).


same

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If one parent gave us one type of gene and the other parent gave us a different type, then we are . . .› HETEROZYGOUS or hybrid – we have

two different alleles.


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With MENDELIAN traits (the type of traits that Mendel studied), heterozygotes DO NOT have a _______ of the two alleles.› Instead, one type of allele dominates –

We show the characteristics of this allele only – it is the ____________ trait.


blend

DOMINANT

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The other version of the trait is still there on half of our chromosomes (so we might still pass it on to our children, depending on meiosis) BUT it DOES NOT affect us right now – it is the ____________ trait.


RECESSIVE

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Whether we are heterozygous, homozygous with the dominant trait, or homozygous with the recessive trait it is called our ___________ (type of genes that we have).

Which trait we _____________ show is our _____________ (the type of allele that is expressed).


GENOTYPE

physicallyPHENOTYPE

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For example, if the __________________ of the eye color gene is brown and the __________________ of the eye color gene is blue, then the person could have the following possibilities:

Mendelian Genetics Overviewdominant allele

recessive allele

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Two blue alleles, bb (one from ______, one from _____).› Genotype would be ______________

___________Phenotype would be ___________.

Mendelian Genetics Overviewmom

dadhomozygousblue eyes

recessive

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Two brown alleles, BB (one from mom, one from dad).› Genotype would be ______________

____________Phenotype would be _____________.


homozygous

brown eyesdominant

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Two brown alleles, Bb (one from mom, one from dad).› Genotype would be ______________

Phenotype would be _____________.


heterozygous

brown eyes

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Eye color is actually more complicated than that.

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When only _____ trait is being studied in a genetic cross it is called a _____________________.› When parent organisms, called the

________________, are crossed, the resulting offspring are the first filial or _________________.

› When organisms of the F1 generation are crossed, their offspring make up the second filial or, _________________.

Mendelian Genetics Overviewone

monohybrid cross

F1 generation

P generation

F2 generation52


Mendel produced pure strains by allowing plants to self-pollinate for several generations.

These strains were called the __________ generation or P1 strain.

Mendel’s Experiments

parental

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Mendel cross-pollinated two strains and tracked each trait through two generations. (ex. TT x tt)› ________ = plant height› ________ = T (tall), t (short)


TraitAlleles

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P1 cross = __________Mendel’s Experiments

TT x tt

F1 Genotypic ratio =

__________ F1 Phenotypic ratio =

__________

Tt

T

tT t T tT t T t

100%

100%

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Mendel’s ExperimentsThe offspring of this cross were all _________ showing ONLY the __________________ & were called the __________________ generation.

Tt

T

tT t T tT t T t

hybrids

dominant trait

First Filial or F1

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Mendel then crossed two of his F1 planst and tracked their traits; know as ___________.› ________ = plant height› ________ = T (tall), t (short)


TraitAlleles

F1 cross

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F1 cross = __________Mendel’s Experiments

Tt x Tt

F2 Genotypic ratio =

___________________ F2 Phenotypic ratio =

___________________

TT

t

tT T

T tT t t t

1 T T: 2 T t: 1 t t

3 tall: 1 short

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When 2 hybrids were crossed, 75% (3/4) of the offspring showed the dominant trait and 25% (1/4) showed the recessive trait.

Two hybrids ALWAYS create a ______________________________________.

The offspring of this cross were called the __________________.


3 (dominant trait:1(recessive trait) ratio

F2 generation

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Inheritable ___________________ are responsible for all heritable characteristics.

____________ is based on ___________.

Results of Mendel’s Experimentsfactors and genes

Phenotype genotype

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______________ is based on _____________, one from the mother and the other from the father.

True-breeding individuals are homozygous (both alleles) are the same.

Formulated three laws of heredity in the early 1860’s.

Results of Mendel’s ExperimentsEach traittwo genes

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____________________ states that when different alleles for a characteristic are inherited (heterozygous), the trait of only one (the dominant one) will be expressed. The recessive trait’s phenotype only appears in true-breeding (homozygous) individuals.

Mendel’s 3 Laws of HeredityLaw of Dominance

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Law of Dominance

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____________________ states that each genetic trait is produced by a pair of alleles which separate (segregate) during reproduction.

Explains the disappearance of a specific trait in the F1 generation and its reappearance in the F2 generation.

Mendel’s 3 Laws of HeredityLaw of Segregation

Rr

R r

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________________________________ states that each factor (gene) is distributed (assorted) randomly and independently of one another in the formation of __________ (egg or sperm).

Mendel’s 3 Laws of HeredityLaw of Independent Assortment

gametes

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Law of Independent Assortment Explains that different traits are

inherited ________________, if on different chromosomes.

Ex: wrinkled seeds do not have to be yellow. They can be green.

independently

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Law of Independent Assortment Ex. A gamete with RrYy

› R and r – separate into different gametes.

› Y and y – separate into different gamets.

› They can then recombine 4 ways to form gametes:

RY Ry rYry

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Inheritance of Human Traits:Dominant/Recessive

Dark hair / Light hair Non-red hair / Red hair Curly hair / Straight hair Widows peak / Straight or curved

hairline Body hair / Scant body hair Freckles / Normal Dimples / No dimples

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Brown eyes / Gray or blue eyes Normal eyesight / Nearsighted Large Eyes / Small eyes Long eyelashes / Short eyelashes Broad nostrils / Narrow nostrils Roman nose / Straight nose

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Large nose / Small nose Free ear lobe / Attached ear lobe Web fingers / Normal fingers Bent little finger / Parallel little finger Left over right thumb / Right over left

thumb

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A or B blood / O blood Rh+ blood / Rh- blood Normal clotting / Hemophilia Normal / Allergy Tongue roller / Non-roller

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Human Genetics

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Fraternal vs. Identical Twins _______________ develop from a _______

fertilized egg that splits shortly after fertilization.› Since they developed from the ______ egg

they have exactly the same ___________________.

Identical twins

single

samegenetic makeup

74


Fraternal vs. Identical Twins

_______________ develop from ____ eggs that are fertilized by _____ sperms.› They are

completely ___________ people.

Fraternal twins

two

two

different

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Fraternal vs. Identical Twins By studying identical twins, geneticists

learned that _______ seem to have a greater influence than the ________________ on such traits as height, weight, blood pressure, speech patterns, and gestures.

genesenvironment

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Fraternal vs. Identical Twins They have also discovered that _______

play a role in some _________ problems once thought to be caused only by environmental factors.› For instance, genes can cause a

susceptibility to __________ such as diabetes and certain types of cancer.

genesmedical

diseases

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Inherited Diseases: ___________ and ___________________

CANNOT be _________. Certain chemical conditions of the cells

and body tissues important in resistance against infections may be inherited.

Infections

infectious diseasesinherited

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Inherited Diseases: Diseases resulting from abnormal

structure or function of body organs are ______ likely to be hereditary.

more

79


Inherited Diseases: Some diseases that

may be associated with genes are:

› Diabetes› Respiratory allergies› Asthma

› Nearsightedness› Farsightedness› Night blindness

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Inherited Diseases: ___________________ determine the sex of

an individual.› The X chromosomes (___) produce a

________.› An X chromosome paired with a Y

chromosome (___) produces a ______.

Sex chromosomes

XXfemale

XY

male

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Sex Determination: Since only a male can produce a gamete

bearing a Y chromosome, the ________ determines the _____ if the child.

NOTE: The X chromosome contains additional genetic information that the Y chromosome does not have, therefore a male child actually inherits more genetic information from his ________ than his father (a very tiny amount).

fathersex

mother

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Sex-Linked Traits: Traits that occur ______ frequently in one

sex than another

› Males – color blindness and hemophilia

more

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http://www.webexhibits.org/causesofcolor/2.html

Sex-Linked Traits: Occurs because other genes besides the

alleles for sex are also located on the sex chromosomes.

They are ___________ to the normal condition and the Y chromosomes appear to lack genes for these traits.

These traits generally do not show up in _________.

recessive

females

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Punnett Squares:

Use Punnett Squares to solve genetic problems!

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Punnett Squares:

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Practice Problems –MONOHYBRIDS (one trait)

Black coat color in guinea pigs is dominant over white coat color. Using a Punnett square, show the results of crossing a hybrid black with pure white. Then show the results of crossing a hybrid black and a hybrid black.

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Black Trait – B (dominant) White Trait – b (recessive)

Hybrid black – Bb Pure white - bb

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P1 cross = Mendel’s Experiments

Bb x bb Genotypes of

F1 offspring =

2 Bb : 2 bbPhenotypes of F1 offspring =

2 black : 2 white(50% black : 50% white)

Bb

b

bBb bbBb bb

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Black Trait – _______________ White Trait – _______________

Hybrid black – __________ Hybrid black - __________

B (dominant)b (recessive)

BbBb

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P1 cross = __________Bb x Bb Genotypes of

F1 offspring =

______________________ Phenotypes of

F1 offspring =

_____________________

Bb

b

bBb bb

Bb bb

1 BB:2 Bb:1 bb

3 black : 1 white


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Now You Try Some:

1) In pigs, the white color (W) is dominant; the black color (w) is recessive. Using Punnett squares, show the expected results of the following crosses.

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P1 cross = _____________WW x wwGenotypes of F1 offspring =

______________________ Phenotypes of

F1 offspring =

_____________________

Ww

W

wWw Ww 100% Ww

100% white

1a) A pure (homozygous) white pig is mated with a black pig.

Ww Ww101

P1 cross = _____________Ww x WwGenotypes of F2 offspring =

______________________ Phenotypes of

F2 offspring =

_____________________

WW

w

wWW Ww 1

WW:2Ww:1ww

3 white : 1 black

1b) Show a cross between two of the F1 offspring from number 1a. Determine the

genotypes and phenotypes of the offspring in the F2 generations.

Ww ww102

Dihybrids (two traits)

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Dihybrids (two traits)

o Because each parent and offspring are using _____ traits, each one should have __ alleles, __ for each _______.

o Each gamete produced by the P1 generations will contain 2 alleles, on for each trait.

two4 2 trait

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Dihybrid: Eye Color

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DIHYBRIDS (two traits) Example: A plant that is heterozygous

for being tall and having green seeds is crossed with a homozygous yellow and short.› Traits = seed color and plant height› Alleles G = green T = tall

g = yellow t = short

Cross: ______________TtGg x ttgg106

DIHYBRIDS (two traits) Determine the gametes produced by

each parent by using the FOIL method.› TtGg produces four different gametes:

_____ _____ _____ _____

ttgg produces only one gamete: ______

TG Tg tG tg

tg

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TG

tg

tG tgTg

tg

tg

tg

TtGg

TtGg

TtGg

TtGg

ttgg

ttgg

ttgg

ttgg

ttGg

ttGg

ttGg

ttGg

Ttgg

Ttgg

Ttgg

Ttgg

Phenotypes:4 tall/green seeds4 tall/yellow seeds

4 short/green seeds4 short/yellow seeds

Genotypes:4 TtGg : 4 Ttgg: 4 ttGg: 4 ttgg

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Practice - DIHYBRIDS (two traits)

In a dihybrid cross, when two traits are considered, the number of possible combinations of the offspring incraseas. Suppose that black hair (B) is dominant over blonde hair (b) and brown eyes (E) are dominant over blue (e).

What percent of offspring could be expected to have blond hair and blue eyes if: 109


The father has black hair (heterozygous) and brown eyes (heterozygous) and the mother has blonde hair and blue eyes.

Genotype of father = _______ Genotype of mother = _______ Complete the cross using the Punnett

square. Determine the percent of offspring that will have blonde hair and blue eyes.

BbEebbee

110

BE

be

bE beBe

be

be

be

BbEe bbeebbEeBbee25% (4/16) blonde hair and blue eyes

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Both parents have black hair (heterozygous) and brown eyes (heterozygous)

Genotype of father = _______ Genotype of mother = _______ Complete the cross using the Punnett

square. Determine the percent of offspring that will have blonde hair and blue eyes.

BbEeBbEe

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BE

BE

bE beBe

BebE

be

BBEE BbEeBbEEBBEe

BBEe BbeeBbEeBBee

BbEE bbEebbEEBbEE

BbEe bbeebbEeBbee

6.25% (1/16) blonde hair and blue eyes

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blue people of troublesome creek

Documents

father of genetics

certain inherited traits

mutt male

truefalse16genetic terminology

unborn child

bens skin blue

male mutt dog mates

childs genetic