GeneticsGenetics

Yeah-ya!Yeah-ya!

PRACTICEPRACTICE

E = Free ear lobes E = Free ear lobes e = attached ear lobese = attached ear lobes

Cross a heterozygous free-eared male with Cross a heterozygous free-eared male with a woman with attached ear lobesa woman with attached ear lobes

eeee

EeEe

e e

e

E

Genotypic Ratio : 2:2EE – 0

Ee – 2 (50%)Ee – 2 (50%)

Phenotypic Ratio : 2:2Free – 2 (50%)

Attached – 2 (50%)

ee

Ee

e

e

E

Draw the other possible crosses for Draw the other possible crosses for this genethis gene

Use other possible genotypesUse other possible genotypes

Punnett Square TrendsPunnett Square Trends

What process is a punnett square What process is a punnett square showing (predicting)?showing (predicting)?

Independent vs. Dependent Independent vs. Dependent AssortmentAssortment

It’s all about ProbabilityIt’s all about Probability

Old School ThinkingOld School Thinking

MendelMendel

Why Peas?Why Peas?

•Chosen for its 7 Chosen for its 7 easily easily distinguishable distinguishable characteristicscharacteristics•Short life spanShort life span•SmallSmall•Large number Large number of offspringof offspring•Easy to self or Easy to self or cross fertilizecross fertilize

Mendel’s ProcessMendel’s Process

4 Key Findings4 Key Findings

Characters (traits) are influenced by Characters (traits) are influenced by allelesalleles (different forms of the same gene) (different forms of the same gene)Each organism inherits 2 “factors” (alleles) Each organism inherits 2 “factors” (alleles) for each trait – one from each parentfor each trait – one from each parentOne allele will dominate over the recessive One allele will dominate over the recessive oneoneAlleles segregate during gamete Alleles segregate during gamete productionproduction

SEED SHAPE

SEED COLOR

CHROMOSOMESCHROMOSOMES

LETTERS are ALLELES

THREE DIFFERENT POSSIBILITIES FOR A GENE

HOMOZYGOUS

DOMINANT

HOMOZYGOUS

RECESSIVE

HETEROZYGOUS

DOMINANT

MEIOSISMEIOSIS

4 CELLS WITH ‘R’ ALLELE FOR THIS GENE

How did Mendel find true-breeding How did Mendel find true-breeding plants?plants?

Any ideasAny ideas

TestcrossTestcross

What does it mean to be dominant?What does it mean to be dominant?

Different types of inheritanceDifferent types of inheritance

Complete DominanceComplete Dominance – 50 copies of the – 50 copies of the functional protein functional protein gives the same effect gives the same effect as 100 copies as 100 copies ((haplosufficiencyhaplosufficiency))– PKUPKU (genetic disorder (genetic disorder

where phenylalanine where phenylalanine cannot be broken cannot be broken down – missing down – missing enzyme)enzyme)

Can cause mental Can cause mental retardation if untreatedretardation if untreated

Incomplete Dominance – 50 copies is not Incomplete Dominance – 50 copies is not sufficient (Flower color in snapdragons)sufficient (Flower color in snapdragons)– FF – produces 100 red pigment molecules FF – produces 100 red pigment molecules

(very dense) – seen as red(very dense) – seen as red– Ff – produces 50 red pigment molecules (less Ff – produces 50 red pigment molecules (less

dense) – seen as pinkdense) – seen as pink– ff – produces no red pigment molecules – ff – produces no red pigment molecules –

seen as whiteseen as white

Codominance – 2 different proteins can be Codominance – 2 different proteins can be made by a single gene (A&B blood types)made by a single gene (A&B blood types)– When the A allele is present – A antigens are When the A allele is present – A antigens are

made and seen on the RBC surfacemade and seen on the RBC surface– When the B allele is present – B antigens are When the B allele is present – B antigens are

made and seen on the RBC surfacemade and seen on the RBC surface– When neither are present – no antigens are When neither are present – no antigens are

presentpresent– When both alleles are present – both antigens When both alleles are present – both antigens

are seen on the surface of the RBC’sare seen on the surface of the RBC’s

Multiple Alleles – more than 2 Multiple Alleles – more than 2 possible alleles for a genepossible alleles for a gene

Rh Factor – normal autosomal Rh Factor – normal autosomal inheritanceinheritance

Blood Types and PersonalityBlood Types and PersonalityAccording to the Japanese...According to the Japanese...

Type OType OYou want to be a leader, and when you see You want to be a leader, and when you see something you want, you keep striving until you achieve something you want, you keep striving until you achieve your goal. You are a trendsetter, loyal, passionate, and your goal. You are a trendsetter, loyal, passionate, and self-confident. Your weaknesses include vanity and self-confident. Your weaknesses include vanity and jealously and a tendency to be too competitive.jealously and a tendency to be too competitive.Type AType AYou like harmony, peace and organization. You You like harmony, peace and organization. You work well with others, and are sensitive, patient and work well with others, and are sensitive, patient and affectionate. Among your weaknesses are stubbornness affectionate. Among your weaknesses are stubbornness and an inability to relax.and an inability to relax.Type BType BYou're a rugged individualist, who's straight You're a rugged individualist, who's straight forward and likes to do things your own way. Creative forward and likes to do things your own way. Creative and flexible, you adapt easily to any situation. But your and flexible, you adapt easily to any situation. But your insistence on being independent can sometimes go too insistence on being independent can sometimes go too far and become a weakness.far and become a weakness.Type ABType ABCool and controlled, you're generally well-liked Cool and controlled, you're generally well-liked and always put people at ease. You're a natural and always put people at ease. You're a natural entertainer who's tactful and fair. But you're standoffish, entertainer who's tactful and fair. But you're standoffish, blunt, and have difficulty making decisions.blunt, and have difficulty making decisions.

Genes on the Male Sex Chromosomes

DOMINANT RECESSIVE

XHXH XHXh

XHY XhY

XH

Y

XH Xh

IV.IV. Sex-linked InheritanceSex-linked InheritanceA.A. Color Blindness – recessive, linked to the X Color Blindness – recessive, linked to the X

chromosomechromosome1.1. Cannot distinguish between colors like red Cannot distinguish between colors like red

and greenand green2.2. Genotypes:Genotypes:

a.a. XXCCXXCC – normal female, non carrier – normal female, non carrierb.b. XXCCXXc’c’ – normal female, carrier – normal female, carrier (may pass (may pass

recessive allele on to sons and/or recessive allele on to sons and/or daughters)daughters)

c.c. XXc’c’XXc’c’ – colorblind female – colorblind female (will pass (will pass recessive allele to all childrenrecessive allele to all children

d.d. XXCCY – normal maleY – normal malee.e. XXc’c’Y – colorblind male Y – colorblind male (will pass recessive (will pass recessive

allele to daughters only)allele to daughters only)