1. Copy the chart: Quick Question 1/31
Physical GENETIC Traits (SPECIFIC!)
Similarities
Differences 1) 2) 3) 4) 5)

2. Figure 13.1
Figure 13.1 What accounts for family resemblance?

4. Genetics Assignments:
Ch. 9 Vocab – DUE Friday, 2/2
Ch. 9 Objectives – DUE Monday, 2/5
Family Photo and Character Traits List (5 similarities/5 differences) – DUE BLOCK Tues 2/6 or Weds 2/7

5. GENETICS: Patterns of Inheritance
Chapter 9
GENETICS:
Patterns of Inheritance

6. Genetics is the scientific study of heredity and variation
Living organisms are distinguished by their ability to reproduce their own kind
Genetics is the scientific study of heredity and variation
Heredity is the transmission of traits from one generation to the next “The DNA Journey”
Variation is demonstrated by the differences in appearance that offspring show from parents and siblings
© 2011 Pearson Education, Inc.

7. The historical roots of genetics:
Early 19th century: traits from mom and dad blend like paints to form kid’s traits
Gregor Mendel (1840’s) : “Father of modern genetics”
Mendel crossed pea plants that differed in certain characteristics (traits) and traced from generation to generation; used a mathematical approach
Why did he choose pea plants?
Crossing of traits:
Self fertilize (True breed) – cross pollen and egg from same parent plant to get identical offspring
Cross Fertilize (hybrid) – cross pollen from one parent plant with the egg of a different parent plant
Gregor mendel

8. And so on… P generation is true-breeding – Parent generation
F1 generation = Hybrid offspring of P (parents)
F2 generation = offspring of F1 plants crossed
F3 generation = offspring of F2 plants crossed
And so on…
Parents (P)
White
Purple
Offspring (F1)

9. Genes- units that determine heritable traits
*Genes are segments of DNA on a chromosome, which code for EACH different trait
Flower color
Flower position
Seed color
Seed shape
Pod color
Pod shape
Stem length
Purple
White
Axial
Terminal
Round
Wrinkled
Inflated
Constricted
Tall
Dwarf
Green
Yellow

10. For each characteristic (trait), an organism inherits 2 alleles, one from each parent.
Think of TRAITS as CATEGORIES and ALLELES as OPTIONS within each category!
P generation
(true-breeding parents)
F1 generation
F2 generation
Purple flowers
White flowers 
All plants have purple flowers
Fertilization among F1 plants (F1  F1)
of plants have purple flowers 3 4
of plants have white flowers 1
Examples:
Flower Color (trait)
Purple or White (alleles)

11. Phenotype = physical appearance of the allele for a specific trait (purple/white flower for flower color trait)
Genotype = genetic makeup the alleles that represent the phenotype (one dominant, one recessive; or 2 dominant alleles and 2 recessives)
DNA from the Beginning Animations

12. Dominant and Recessive Alleles:
If the 2 alleles of an inherited pair are different, then one determines the organism’s appearance and is called the dominant allele. (Dominant will usually show up more often!)
The other allele has no noticeable effect on the organism’s appearance and is called the recessive allele. (Is present but does not show up in the appearance)
* If dominant allele is present, it takes over and outweighs the recessive!

13. Dominant and Recessive alleles:
CAPITAL letters = DOMINANT alleles
lower case letters = recessive alleles.
*MUST USE SAME LETTER FOR EACH TRAIT! (Doesn’t matter the letter you choose!)
Example:
Flower Color (trait) T = purple, t = white
Pea Color R=yellow, r =green

14. HOMOZYGOUS and HETEROZYGOUS
When 2 of the SAME ALLELES are present, it is HOMOZYGOUS for that trait.
HH = homozygous dominant
hh = homozygous recessive
When 2 DIFFERENT alleles are present, it is termed HETEROZYGOUS for the trait.
Hh= heterozygous
With
homozygous,
you must clarify
which allele-
either
Dominant
or recessive!

15. PUNNETT SQUARE:
Shows a genetic mixing (cross) of alleles from both parents for specific traits.
Used to PREDICT PROBABILITIES and see inheritance patterns for specific traits!

16. Trait= Flower Color H h Parent #2 H =purple h = white Hh Hh Hh Hh#1 Hh Hh

17. Probability of one offspring from parent cross!
Trait= Flower Color
* If Dominant allele is present, it takes over and outweighs the recessive!
H =purple h = white H h
Genotype =genetic makeup (represented by letters!)
Parent 1 = hh homozygous recessive
Parent 2 = HH homozygous dominant
Offspring= 100% Hh Heterozygous Hh Hh
Probability of one offspring from parent cross!
Phenotype =physical appearance (what the letters represent!) Hh
Parent 1 = white
Parent 2 = purple
Offspring= 100% purple Hh

18. LET’S PRACTICE!!!

19. 9.8 Genetic traits in humans can be tracked through family pedigrees.
Pedigree Key Dd
Joshua
Lambert
Abigail
Linnell
D ?
John
Eddy
Hepzibah
Daggett dd
Jonathan
Elizabeth
Dd Dd dd Dd Dd Dd dd
Female Male
Deaf
Hearing
Female
Male
Mating
Offspring
Figure 9.8 B

20. Recessive Disorders- Most human genetic disorders are recessive
Parents
Offspring
Sperm
Normal Dd 
D d
Eggs D d DD
(carrier) dd
Deaf
Figure 9.9 A

21. Pea Plant Inheritance Patterns- Complete Dominance

22. Homologous chromosomes bear the two alleles for each TRAIT
Each trait has the same locus (point) on homologous chromosomes
Genotype: RR aa Bb
Heterozygous R a b B
Gene loci
Recessive allele
Dominant allele
Homozygous for the dominant allele
Homozygous for the recessive allele
Flower Color?
Pea Color?
Plant Height?

23. Mendel’s 2 Main Laws of Inheritance
1) Law of Segregation (separate)- allele pairs from each parent separate from each other during the production of gametes (sperm/eggs)
Mendel’s 2 Main Laws of Inheritance

24. Mendel’s 2 Main Laws of Inheritance
2) Law of Independent Assortment- States that alleles of ONE trait separate independently of allele pairs from a DIFFERENT TRAIT during gamete formation (more than one trait involved)
*During meiosis, various combinations can end up in the different gametes, so all possibilities for trait phenotypes!
Mendel’s 2 Main Laws of Inheritance

25. Table 9.9

26. Dominant Disorders- Some human genetic disorders are dominant
Parents
Offspring
Sperm
Dwarf Dd
Normal dd 
D d
Eggs d
Achondroplasia – cause of dwarfism
Figure 9.9 B

27. 9.10 New technologies can provide insight into genetic legacy
Identifying Carriers
For an increasing number of genetic disorders, tests are available that can distinguish carriers of genetic disorders and can provide insight for reproductive decisions
Fetal Testing: Amniocentesis and chorionic villus sampling (CVS) allow doctors to remove fetal cells that can be tested for genetic abnormalities
Fetal Imaging- Ultrasound imaging uses sound waves to produce a picture of the fetus

28. Chorionic villus sampling (CVS)
Figure 9.10 A
Amniocentesis
Chorionic villus sampling (CVS)
Ultrasound
monitor
Fetus
Uterus
Amniotic
fluid
Fetal
cells
Several
weeks
Biochemical
tests
hours
Cervix
Suction tube inserted
through cervix to extract
tissue from chorionic villi
Needle inserted
through abdomen to
extract amniotic fluid
Centrifugation
Placenta
Chorionic
villi
Karyotyping

29. Ethical Considerations
Newborn Screening
Some genetic disorders can be detected at birth, by simple tests that are now routinely performed in most hospitals in the United States
Ethical Considerations
New technologies such as fetal imaging and testing raise new ethical questions
(Think about “Designer Babies”!)

30. NON-MENDELIAN GENETICS
ALL OF THE FOLLOWING ARE EXCEPTIONS TO MENDEL’S RULES!!!
Mendel’s principles are valid for all sexually reproducing species, HOWEVER, genotype often does NOT dictate phenotype in the simple way his laws described.

31. 9.11-9.23 NON-MENDELIAN GENETIC PATTERNS
When an offspring’s phenotype in the heterozygous in between the phenotypes of its parents. (3rd phenotype shows up!)
P generation
F1 generation
F2 generation
Red RR
Gametes 
White rr
Sperm
Eggs
Pink Rr R r rR 1 2
Incomplete dominance
EXAMPLES: Roses, Snapdragons
Figure 9.12 A

32. 9.11-9.23 NON-MENDELIAN GENETIC PATTERNS
In a population, when 2 or more allele options exist for a single trait.
Codominance
EXAMPLES: Roan Fur, Speckled Chickens,
AB Blood Type
Figure 9.12 A

33. 9.11-9.23 NON-MENDELIAN GENETIC PATTERNS
In a population, when 2 or more allele options exist for a single trait.
Multiple Alleles
EXAMPLES: ABO Blood Types
AB Type is also CODOMINANT!
Figure 9.12 A

34. Figure 9.13

36. 9.11-9.23 NON-MENDELIAN GENETIC PATTERNS
Alleles found on more than one gene location; creates a multiple variations of phenotypes
Polygenic
EXAMPLES: Human Skin Color

37. 9.11-9.23 NON-MENDELIAN GENETIC PATTERNS
pattern of sex-linked genes is visible in one sex over the other, females or males.
Typically on X chromosome
Males receiving a single X-linked allele from his mother will have the disorder
Female has to receive the mutated allele from both parents to be affected
Sex Linked
EXAMPLES:
Baldness,
Hemophilia

39. Examples: Hemophilia, Color Blindness, and Duchenne Muscular Dystrophy
Sex Linked
Most sex-linked human disorders are due to recessive alleles and are mostly seen in males
Examples: Hemophilia, Color Blindness, and Duchenne Muscular Dystrophy
Queen
victoria
Albert
Alice
Louis
Alexandra
Czar
Nicholas II
of Russia
Alexis
Figure 9.24 A
Figure 9.24 B

40. Example: Hypertrichosis Pinnae Auris
Sex Linked
Linked to Y chromosome (only males)
Example: Hypertrichosis Pinnae Auris
(aka HAIRY EARS!!!)

41. Extra Credit Questions regarding talk will be on the Ch. 9 Test!
Watch “The Ethical Dilemma of Designer Babies” TED Talk on class website!
Extra Credit Questions regarding talk will be on the Ch. 9 Test!