9-1 How come you look like you? It’s in your genes!

Transmission of characteristics from parents to offspring is called ___________________. The STUDY of how those characteristics are passed on from one generation to the next is called ___________________

The Father of Genetics is _________________, a monk whose study of genetic traits was the beginning of our understanding about how genes work.

Mendel designed experiments using _________________________. He looked at different observable CHARACTERISTICS or ______________

Pea Characteristics

A plant that ALWAYS produces offspring with a certain trait are called ___________ for that trait.

Remember all body cells have 2 copies of every gene, so to breed pure the 2 parent gene choices must be the_________. _______ red flower alleles

PURE white flowered plants have ______ WHITE flower alleles

Mendel combined genes from 2 PURE parent plants and recorded the kinds of ___________ produced. In his experiments the 1 st plants crossed were called the ____ generation. ( P is for parental)

GENETIC EXPERIMENTS ____ generation (parental) ____ generation (filial=offspring) ___ generation

GENETIC EXPERIMENTS Image modified from:

When Mendel crossed PURE PLANTS with 2 choices for a trait: He found 1. ___________________________________ BUT 2. ___________________________________ Only _____trait showed in the F 1 generation Missing trait reappeared in the F 2 generation in a ________ ratio

Mendel decided that there must be a_______ of “factors” controlling each trait and that one factor must be able to _______ the other.

We now know that Mendel’s “factors” are _________ carried on the pair of________________ _________________

_______________ are different gene choices for a trait.

__________________ = An allele that MASKS the presence of another allele __________________ = An allele that IS MASKED BY the presence of another allele

WHAT DOES MEIOSIS HAVE TO DO WITH IT?

MENDEL’S LAWS LAW OF ____________________ The pair of factors is segregated (or separated) during the formation of gametes. Image modified from:

LAW OF __________________________ the factors are distributed to gametes independently of other factors Image modified from:

MENDEL’s LAWS of SEGREGATION & INDEPENDENT ASSORTMENT happen because of the way the chromosomes move during __________________

GENETIC CROSSES 9-2

DOMINANT/RECESSIVE Dominant gene is represented by a ____________ letter. (usually the first letter of the trait) Recessive gene is represented by the SAME _________________ letter. EX: Tall = ______ Short =______ NOT S for short

HOMOZYGOUS HETEROZYGOUS When both alleles in the pair are the SAME the organism is _______________ or __________ EX: TT or tt When both alleles in the pair are DIFFERENT the organism is _________________ or _____________ Ex: Tt

PHENOTYPE/GENOTYPE The genetic makeup of an organism is its _____________ The appearance of an organism is its _____________

PUNNETT SQUARES are used to show possible offspring of a cross between 2 parents Parent genes go at top and on left side Boxes show possible combinations Animation from:

____________________ is the likelihood that a specific event will occur It can be written as a: Fraction 1/4 Percent 25% Ratio 1:3

IN PEA PLANTS Tall is dominant over short TALL = ____ SHORT = ____

PURE TALL parent What genes can it give? T T _________   T T

TT

PURE SHORT parent What genes can it give? t t _________   t t

ALL of the offspring 4/4 100% will be TT t t GENOTYPE _____ PHENOTYPE _______

HYBRID TALL parent What genes can it give? T t _________   T t

Tt

GENOTYPES ¼ = _____ ½ = _____ ¼ = _____ Tt T t T TT T T t T tT t t tt t PHENOTYPES _______ ____________ _______ ____________

MAKING A CROSS with only ONE gene trait = ____________________ A Punnett square for a MONOHYBRID CROSS looks like this:

TESTCROSS used to tell what genes an organism has Cross an UNKNOWN parent with a ____________________________ and see results Offspring give a clue about the unknown parent’s genes

TESTCROSS used to tell what genes an organism has Example: The genes of a TALL PARENT are UNKNOWN - COULD HAVE _____

TESTCROSS tttt T T T t tt tt Tt Tt Tt tt All offspring will be TALL 50% will be TALL 50% will be SHORT

DEAF DOGS Deafness in dogs is DOMINANT (D) over the ability to hear (d) A deaf dog could have 2 possible GENOTYPES______ How do we tell which one it is?

TESTCROSS DEAF PARENT WITH PURE HEARING PARENT dddd D D D d dd dd Deaf Deaf Deaf Hearing Deaf Hearing If you get some hearing puppies, you know parent was Dd.

GENES are more complicated than MENDEL thought Some traits have more than two allele choices EX: eye color

GENES are more complicated than MENDEL thought Some traits are determined by more than one gene EX: Human height

GENES are more complicated than MENDEL thought Traits determined by more than one gene have lots of “in-between” phenotypes There aren’t just SMART people and DUMB people…. there is a whole range of intelligences in-between

GENES are more complicated than MENDEL thought KINDS OF DOMINANCE ____________________

COMPLETE DOMINANCE Dominant allele masks the recessive one Recessive allele returns in a 3:1 ratio in the F 2 generation

INCOMPLETE DOMINANCE Don’t see expected 3:1 ratio in F 2 generation Organisms with one dominant and one recessive allele show a blended in-between trait

INCOMPLETE DOMINANCE ALLELES BLEND to produce an INTERMEDIATE PHENOTYPE Don’t see the expected 3:1 ratio in the F2 generation

CO-DOMINANCE Both traits are expressed at same time (NO BLENDING) in heterozygote Has BOTH RED hair and WHITE hair

CO-DOMINANCE Both traits are expressed together (NO BLENDING) in heterozygote Persons with an A gene AND a B gene have blood type AB

BLOOD TYPES have more than 2 allele choices Proteins with SUGARS attached help cells recognize ___________ Called _______________

BLOOD TYPES have more than 2 allele choices The protein and sugar that is attached is determined by genes Allele choices are: _____________

BLOOD TYPES An A gene tells the cell to put “A” glycoproteins on its surface

BLOOD TYPES An B gene tells the cell to put a different “B” glycoprotein on its surface

BLOOD TYPES An O gene tells the cell NOT to put anything on the surface

A and B are CO-DOMINANT A cell with an A and a B gene has BOTH “A” and “B” glycoproteins on its surface

BLOOD TYPES & ALLELES ALLELEBLOOD TYPE AAA AOA BBB BOB OOO AB

BLOOD TYPES YOU ARE NOT ME! IMMUNE SYSTEM ATTACKS! Body images modified from: YOU’RE NOT DIFFERENT FROM ME!

BLOOD TYPES YOU ARE NOT ME! IMMUNE SYSTEM ATTACKS! Body images modified from: YOU’RE NOT DIFFERENT FROM ME!

BLOOD TYPES YOU ARE NOT ME! IMMUNE SYSTEM ATTACKS! Body images modified from: YOU’RE LIKE ME!

BLOOD TYPES Body images modified from: YOU’RE NOT DIFFERENT FROM ME! O can donate to EVERY BLOOD TYPE = UNIVERSAL DONOR! Nothing on surface to recognize as “NOT SELF”

BLOOD TYPES Body image modified from: AB can RECEIVE FROM EVERY BLOOD TYPE = UNIVERSAL RECIPIENT

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

OTHER BLOOD TYPES Rh + Rh -

OTHER BLOOD TYPES NO PROBLEMS IF: Imagea modified from: MOM & BABY are both + MOM is + & BABY is -

OTHER BLOOD TYPES PROBLEMS IF: Imagea modified from: MOM is - & BABY is + 1 st baby OK but few baby cells entering mom’s bloodstream put mom’s immune system on alert for + cells. Next + baby, mom’s immune system can attack baby as it is growing Shot after 1 st birth prevents alert

DIHYBRID CROSSES ( 2 traits)

MAKING A CROSS with TWO gene traits = ____________________ A Punnett square for a DIHYBRID CROSS looks like this:

R R Y YR R Y Y r r y yr r y y HOMOZYGOUS ROUND YELLOW HOMOZYGOUS WRINKLED GREEN X

POSSIBLE GAMETES?

ry RY 100% of offspring = _______ genotype _______________________ phenotype RrYy RrYy RrYyRrYy RrYy RrYy

R r Y yR r Y y R r Y yR r Y y HETEROZYGOUS ROUND YELLOW X

POSSIBLE GAMETES?

RYRyrYry RY Ry rY ry Sign of a heterozygous dihybrid cross is a _____________ ratio in offspring. ____ Round & Yellow ____ Round & green ____ Wrinkled & yellow ____ wrinkled & green

9:3:3:1 ____ DOMINANT TRAIT 1 ; DOMINANT TRAIT 2 ____ DOMINANT TRAIT 1; RECESSIVE TRAIT 2 ____ RECESSIVE TRAIT 1; DOMINANT TRAIT 2 ____ RECESSIVE TRAIT 1; RECESSIVE TRAIT 2