Exploring Mendelian Genetics

http://www.eslkidstuff.com/images/tallshort.gif

http://sps.k12.ar.us/massengale/genetics%20tutorial.htm

Chromosomes that determine the sex of an organism = _________________

All other chromosomes = _________________

Sex chromosomes

autosomes

Humans have two sex chromosomes

and _____ autosomes

X Y44

http://www.angelbabygifts.com/

SEX DETERMINATIONXX =

XY =

female

male

Who decides?

Mom can give X

Dad can give X or y

SO ____ determines sex of the baby.

If dad gives X with mom’s X = girlIf dad give y with mom’s X = boy

X X

X

y

X X X X

X y X y

Dad

HEMOPHILIA CAUSE:

Mutation in genes for __________________ carried ______ chromosome

Blood clotting proteins are missing so person with this disorder can’t stop bleeding when injured; can ________________ from minor cuts or suffer internal bleedingfrom bruises or bumps. _____________ in ______ because it is X-linked, but females with ______ recessive hemophilia alleles will also show the trait.

bleed to death

Blood clotting proteinson X

More common males

TWO

• Colorblindness and pattern baldness are also sex-linked recessive traits carried on the X chromosome

Males ONLY HAVE ONE X

They eitherhave the disorder

DEFECTIVE NORMAL

They are normal

Or

FEMALES HAVE TWO X CHROMOSOMES

Females have one normalgene that works.

NORMAL DEFECTIVEDEFECTIVE

Females __________defective recessivealleles to show the disorder

need 2

The X chromosome in males . . . flies WITHOUT a copilot!

. . . there’s NO BACK UP X to help them!

X-linked cross

Dad is not colorblind

Mom is colorblind

What is the probability of having acolorblind boy? What is the probability of having a colorblind girl?

Xb Xb

XB

y

XB Xb XB Xb

Xb y Xb y

All boys will be colorblind

No girls will be colorblind

Girls with this genotype: XB Xb

don’t show the COLORBLIND trait

They have a “backup” X.

BUT. . . . They can pass the gene onto their offspring.

http://www.biochem.arizona.edu/classes/bioc460/spring/rlm/RLM36.1.html

A heterozygous person who carries a recessiveallele for a genetic disorder, but ________ show the trait themselves is called a_____________CARRIER

doesn’t

Xb Xb

XB

Y

XB Xb XB Xb

Xb Y Xb Y

GENES are more complicated than MENDEL thought

Some traits are determined by ____________________________= __________________

EX: human height. intelligence,

skin & eye colorhttp://www.bcps.org/offices/lis/models/life/images/grow.JPG

POLYGENIC TRAITMORE THAN ONE GENE

GENES are more complicated than MENDEL thought

Traits determined by ____________ _________ have _____“___________” phenotypes

http://www.newtonswindow.com/problem-solving.htm

There aren’t just SMART people and DUMB people…. there is a ________________of intelligences in-between

MORE thanONE gene many

in-between

whole range

GENES are more complicated than MENDEL thought

KINDS OF DOMINANCE

____________________

____________________

____________________

COMPLETE DOMINANCEINCOMPLETE DOMINANCECO-DOMINANCE

COMPLETE DOMINANCE

__________ allele _______ the ___________ one

PATTERN ?____________ allele ________

in a _____ratio in the ____ generation

Dominant masks recessive

Recessivereturns

3:1F2

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookTOC.html

INCOMPLETE DOMINANCE

__________ expected

_____ ratio in

F2 generation

_____________ organisms with one dominant and one recessive allele show a _________ in-between traitBLENDED

DON’T SEE

3:1

Heterozygous

Image modified from: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookTOC.html

Intermediate Inheritance—How it works

• Ex: Andalusian Chickens come in Black, White, or Blue.

• White and Black Colors are not dominant over each other.

Intermediate Inheritance—How it works

• Blue is the intermediate trait, created when a Black Color allele and a White color allele are combined.

Intermediate Inheritance—How it works

• When writing these Intermediate alleles, the “C” for Color is used.

• With the “C”, a

superscript “W” or

“B” is used to show

which Intermediate

alleles it has.

Intermediate Inheritance—How it works

CWCW = White CBCB = Black

CBCW = Blue chicken Tasty Chicken…

Intermediate Inheritance—How it works

• A Punnett Square testcross is the same as a Mono-hybrid cross,

but would place

each intermediate

allele in each section

of the diagram.

CO-DOMINANCE_______ traits are expressed at ___________

(_____________________) in heterozygote

A ________HORSE has ______________ hair and __________ hair side by side

BOTH SAME TIME

ROAN

BOTH RED WHITE

NO BLENDING

Coat color in Shorthorn cattle is the result of Codominance

• R= Red

• W= White

CR CW

CRCR CR CR CW

CW CR CW CWCW

CO-DOMINANCEBoth traits are expressed together

(NO BLENDING) in heterozygote

Persons with an A alleleAND a B allele have blood type AB

GENES are more complicated than Mendel thought

Some traits have ____________ allele __________

= ____________________

EX: blood type

Allele choices ___ ___ ___

MULTIPLE ALLELE TRAIT

A B O

MORE than 2 choices

BLOOD TYPES have more than 2 allele choices= _________________________

The pattern of sugars that is attached is determined by genes

Allele choices are:

_____ ____ ____ A B O

MULTIPLE ALLELE TRAIT

BLOOD TYPESAn A allele tells

the cell to put

“A” glycoproteins

on its surface

BLOOD TYPES

A B allele tells

the cell to put a

different “B”glycoprotein

on its surface

BLOOD TYPES

An O allele tells

the cell NOT to put anything on the surface

A and B are CO-DOMINANT

A cell with BOTH an A and a B allele has BOTH“A” and “B” glycoproteins on its

surface

BLOOD TYPES & ALLELES

GENOTYPEPHENOTYPE

(BLOOD TYPE)

IAIA

IAi

IBIB

IBi

ii

IAIB

A

A

B

B

O

AB

B and O see Aas Different! IMMUNE SYSTEM

ATTACKS!Body images modified from: http://www.new-fitness.com/images/body_shapes.jpg

A and AB see Aas “like me”

DONORBLOOD

A and O see Bas Different! IMMUNE SYSTEM

ATTACKS!Body images modified from: http://www.new-fitness.com/images/body_shapes.jpg

B and AB see Bas “like me”

DONORBLOOD

Body images modified from: http://www.new-fitness.com/images/body_shapes.jpg

YOU DON’T HAVE ANYTHING I DON’T HAVE!

____ can donate to EVERY BLOOD TYPE = _____________________

Nothing on surface to recognize as “NOT SELF”

UNIVERSAL DONOR

O

DONORBLOOD

A, B, and O see AB as Different!

IMMUNE SYSTEM ATTACKS!Body images modified from:

http://www.new-fitness.com/images/body_shapes.jpg

Only AB sees ABas “like me”

DONORBLOOD

Body image modified from: http://www.new-fitness.com/images/body_shapes.jpg

______ can RECEIVE FROM EVERY BLOOD TYPE = ________________________UNIVERSAL RECIPIENT

AB

AB can only GIVE to ABBUT . . .

BLOOD TYPE FREQUENCY IN USA

http://www.reachoutmichigan.org/funexperiments/agesubject/lessons/newton/BldTyping.html

A 40%B 10%

AB 4%O 46%