Exploring Mendelian Genetics

Chromosomes that determine the sex of an organism = _________________ All other chromosomes = _________________ Sex chromosomes autosomes Humans have two sex chromosomes and _____ autosomes X Y 44

SEX DETERMINATION XX = 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 = girl If dad give y with mom’s X = boy X X X y X 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 bleeding from 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 proteins on 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 either have the disorder DEFECTIVE NORMAL They are normal Or

FEMALES HAVE TWO X CHROMOSOMES Females have one normal gene that works. NORMALDEFECTIVE Females __________ defective recessive alleles 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 a colorblind boy? What is the probability of having a colorblind girl? XbXb XbXb XBXB y XB XbXB Xb XB XbXB Xb Xb yXb yXb yXb y All boys will be colorblind No girls will be colorblind

Girls with this genotype: X B X b don’t show the COLORBLIND trait They have a “backup” X. BUT.... They can pass the gene onto their offspring.

A heterozygous person who carries a recessive allele for a genetic disorder, but ________ show the trait themselves is called a _____________ CARRIER doesn’t XbXb XbXb XBXB Y XB XbXB Xb XB XbXB Xb Xb YXb YX b Y

GENES are more complicated than MENDEL thought Some traits are determined by ____________________________ = __________________ EX: human height. intelligence, skin & eye color POLYGENIC TRAIT MORE THAN ONE GENE

GENES are more complicated than MENDEL thought Traits determined by ____________ _________ have _____ “___________” phenotypes There aren’t just SMART people and DUMB people…. there is a ________________ of intelligences in-between MORE than ONE gene many in-between whole range

GENES are more complicated than MENDEL thought KINDS OF DOMINANCE ____________________ COMPLETE DOMINANCE INCOMPLETE DOMINANCE CO-DOMINANCE

COMPLETE DOMINANCE __________ allele _______ the ___________ one PATTERN ? ____________ allele ________ in a _____ratio in the ____ generation Dominant masks recessive Recessive returns 3:1 F2F2

INCOMPLETE DOMINANCE __________ expected _____ ratio in F 2 generation _____________ organisms with one dominant and one recessive allele show a _________ in-between trait BLENDED DON’T SEE 3:1 Heterozygous Image modified from:

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 C W C W = WhiteC B C B = Black C B C W = Blue chickenTasty 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 CRCR CWCW CRCR CR CRCR CR CR CWCR CW CWCW CR CWCR CW CWCWCWCW

CO-DOMINANCE Both traits are expressed together (NO BLENDING) in heterozygote Persons with an A allele AND 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 BO 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: _____________ ABO MULTIPLE ALLELE TRAIT

BLOOD TYPES An 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 GENOTYPE PHENOTYPE (BLOOD TYPE) IAIAIAIA IAiIAi IBIBIBIB IBiIBi ii IAIBIAIB A A B B O AB

B and O see A as Different! IMMUNE SYSTEM ATTACKS! Body images modified from: A and AB see A as “like me” DONOR BLOOD

A and O see B as Different! IMMUNE SYSTEM ATTACKS! Body images modified from: B and AB see B as “like me” DONOR BLOOD

Body images modified from: 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 DONOR BLOOD

A, B, and O see AB as Different! IMMUNE SYSTEM ATTACKS! Body images modified from: Only AB sees AB as “like me” DONOR BLOOD

Body image modified from: ______ can RECEIVE FROM EVERY BLOOD TYPE = ________________________ UNIVERSAL RECIPIENT ABAB AB can only GIVE to AB BUT...

BLOOD TYPE FREQUENCY IN USA A40% B10% AB4% O46%