Word PartsNEW

Pheno – physical characteristics

Geno – genetic make up

Zygous – joined Co – with/together In – not

OLD Hetero – different Homo – same Mono – one Di - two

GeneticsThe Study of Heredity

Scientist Gregor Mendel – created study

of heredity using a garden pea. AKA “Father of Genetics”

Lead to “Laws of Mendelian Inheritance

Mendel’s Principles1. Law of Dominance – some alleles

are DOMINANT & others are recessive

2. Law of Probability – the likelihood an event will occur; predicts outcome of crosses

3.Law of Segregation – alleles separate & go to each gameteHomo Dom (TT) Hetero (Tt) Homo Rec (tt)

Draw Sperm and egg for each

4.Law of Independent Assortment– genes separate independently of each other (Blonde Hair & Blue Eyes)

Other Terms:

Self Pollinating – cross male with female part on same flower

True Breeding – self pollinating that produces identical offspring

Parents are called (P1) 1st Generation- Filial (F1) 2nd Generation – (F2)

Types of Crosses

1. Monohybrid – 1 Trait (Dominant and Recessive)

2. Incomplete – blending of traits (Prime’)

3. Co-Dominant – both appear (mix 2 big letters)

4. Dihybrid - 2 Traits (16 box punnett square) 5. Polygenic – traits is determined by many

genes (Blood, Skin Color, Height)

6. Sex-linked – controlled by the 23rd chromosome

Must Know To Do A Cross

Pheno – looks like, use key Geno – letters, use key AA – Homo Dom Aa – Hetero aa – Homo Rec Fraction - # / # Percent – out of 100 % Ratio – # : #

MonohybridHeight:Homo Dom X Homo

Dom (____ X ____)

Pheno: Tall 4/4 100% 4:0 Short 0/4 0% 0:0

Geno:TTTttt

T T T T

T T

T

T

T T T T

T T T T

4/4 100% 4:00/4 0% 0:00/4 0% 0:0

Monohybrid PracticeHeight:Homo Dom X Hetero (____ X ____)

Pheno: TallShort

Geno:TTTttt

T T

T t

T T

T

t

T T T T

T t T t

4/4 100% 4:00/4 0% 0:0

2/4 50% 2:22/4 50% 2:20/4 0% 0:4

Sex Chromosomes – 23rd Pair

Males = X YFemales = X X

Male X Female

Pheno

Geno:

X X

X

Y

X X X X

X Y

X YMales: 2/4 50% 2:2Females: 2/4 50% 2:2

XX: 2/4 50% 2:2XY: 2/4 50% 2:2

Incomplete – Blending & Prime ‘RR = RedR’R’ = WhiteRR’ = Pink

Cross between a Red X White (____ X ____)

Pheno: RedWhitePink

Geno:RRR’R’RR’

RR R’R’

R’

R’

R R

RR’ RR’

RR’ RR’

0/4 0%0/4 0%4/4 100% 0:0:1

0/4 0%0/4 0%4/4 100% 0:0:1

CoDominant – Both Show EquallyBB = BlackWW = WhiteBW = Spotted

Cross between a Black X Spotted(____ X ____)

Pheno: BlackWhiteSpotted

Geno:BBWW BW

BB BW

B

W

B B

BB BB

BW BW

2/4 50% 0/4 0% 2:0:22/4 50%

2/4 50% 0/4 0% 2:0:22/4 50%

Polygenic – Blood - Uses I

Pheno: Geno:

A IA IA Homo or IA i Hetero

B IB IB Homo or IB i Hetero

AB IA IB Hetero

O i i Homo

1. AB is called the Universal Acceptor2. O is called the Universal Donor3. Knowing a person’s blood type is

critical because it could be FATAL4. Rh factor named for “rhesus

monkey” the animal in which it was discovered is the (+) & (-) factor.

5. (+) is dominant & (-) is recessive6. (-) can give to (+) 7. (+) can NOT give to (-)

BloodCross between a Homo A X Hetero B (____ X ____)

Pheno: ABA

Geno: IAIB

IAi

IAIA IBi IA

IA

IB i

IAIB IAi

IAIB IAi2/4 50%2.4 50% 2:2

2/4 50%2.4 50% 2:2

Gamete Formation

Steps1. Determine alleles for parent2. Place a number above each allele3. Join numbers (13, 14, 23, 24) for

gamete formation Similar to (FOIL) in math.

Example One

A homozygous dark blue clown (DDBB) is crossed with a heterozygous dark blue clown (DdBb). What are the possible genotypes for these clowns.

DDBB x DdBb1 2 3 4 1 2 3 4

13 1314 1423 2324 24

DB DBDB DbDB dBDB db

Example 2 A Diploid cell has the following pairs of homologous

chromosomes: SsTt. Due to independent assortment, what is the possible genetic make-up of gametes produced by this organism?

SsTt

1 2 3 4

13142324

STStsTst