1. JH-KEADLE
Genetics and Heredity

2. Learned Behavior Inherited Trait
Look at he list below and decide if each is a learned behavior or an inherited trait
using tools
curly hair
bright feathers
where to hunt for food
what food tastes good
blue eyes
building a shelter

3. Prokaryotes and Eukaryotes
Prokaryotes and eukaryotes both have DNA

4. Prokaryotes Eukaryotes
protists
fungi
plants
animals
archaebacteria
bacteria

5. Goals
We will focus on genetic material and how it is passed from one generation to the next.
All living organisms reproduce and pass traits to their offspring

6. Heredity
The process in which traits pass from parents to offspring

7. Genetics
Scientific study of heredity

8. Traits
Traits
characteristics controlled by genetic material found in the chromosomes
Phenotype – what you can see
Genotype – genetic code for a trait

9. Traits
Where do traits come from?
parents

10. Chromosomes Chromosomes are found in the nucleus
Chromosomes are made of DNA

11. Chromosomes
The piece of yarn on your desk is a model of the amount of genetic material inside each one of your cells.
Human cells have 46 chromosomes (except the sperm and egg) and if they were connected and stretched out, they would be about 2 meters long
Other organisms have different numbers of chromosomes

12. Chromosomes

13. Chromosomes
This is a karyotype of human chromosomes

14. DNA
DNA is an organic compound called deoxyribonucleic acid

15. DNA DNA is made up of four nitrogenous bases
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
When linked properly, these connected bases create a shape called a double helix (spiral staircase)

16. DNA A G T C C A G T A A C A T T T C A G G T
Guanine (G) always pairs with Cytosine (C)
Thymine (T) always pairs with Adenine (A)
A G T C C A G T A A C A T T T C A G G T

17. Genes
Segment of a DNA molecule that contains information for a specific trait
hair color
eye color
height
chin shape
ear lobes

18. Alleles An allele is a different form of a gene Genes come in pairs
One member of the pair is called an allele
You have 2 or more alleles
for each trait you have

19. Chromosome gene alleles smallest to largest
DNA
smallest to largest
gene→ DNA→ chromosome→ nucleus

20. Dominant and Recessive Alleles
Even though you get at least 2 alleles for each trait, only one shows
The dominant allele will be the one that you see
The recessive allele will be hidden

21. Dominant Allele
If the dominant allele is present in the gene pair, the organism shows the dominant phenotype
represented with a capital letter
curved pinkies
PP or Pp
straight thumb
SS or Ss
rolling tongue
RR or Rr
free ear lobe
FF or Ff
cleft chin
CC or Cc
widow’s peak
WW or Ww
dimples
DD or Dd

22. Recessive Allele
Allele that is hidden if the dominant allele is present
Both alleles in the gene have to be recessive to see the recessive phenotype
Represented with a lower case letter
non -rolling tongue rr
straight pinkies pp
curved thumb ss
attached ear lobe ff
smooth chin cc
no widow’s peak ww
no dimples dd

23. summary Within the nucleus, genes occur in pairs.
A gene is a segment of DNA located on each chromosome
Each gene has a particular form called an allele

24. summary An allele can be either dominant or recessive
If a dominant allele of a gene is present, the dominant trait will appear in an organism
In order for a recessive trait to appear, both alleles of a gene must be recessive

25. Gregor Mendel (1822 – 1884) Father of genetics Lived in Austria
Became a monk
studied genetics using pea plants

26. Mendelian Genetics Mendel looked at several traits in pea plants
pod shape
flower color
plant height

27. Mendelian Genetics Mendel termed traits as dominant or recessive
Punnett square – a chart used to predict what traits the offspring of two parents would have

28. Punnett Square
To set up a Punnett Square, decide which trait is dominant
dominant trait = capital letter
recessive trait = lower case letter
homozygous = two capital or two lowercase (PP or pp)
heterozygous = one capital and one lower (Pp)

29. P P p p Pp Pp Pp Pp Punnett Square Use P for purple flower color
Use p for white flower color
homozygous P P p Pp Pp
homozygous p Pp Pp

30. P p P p PP Pp pp Pp Punnett Square Cross two heterozygous plants

31. Results of the Punnett Square
Each individual from the Punnett Square will have a genotype and a phenotype
Genotype – what the genes are
Phenotype – what it looks like

32. Results of the Punnett Square
Punnett Results
Genotype
Phenotype PP
Homozygous dominant
Purple Flowers Pp
Heterozygous pp
Homozygous recessive
White Flowers

33. Punnett Square Practice
A dog breeder is mating a brown heterozygous lab to a black homozygous lab. Brown is dominant. Set up a Punnett Square and decide what percent of the offspring will be black and brown. ? X =

34. b B b Bb bb Bb bb b Bb One parent is heterozygous brown
B = brown
b = black Bb
One parent is heterozygous brown
One parent is homozygous black bb b B b Bb bb Bb bb b

35. Bb Bb Bb Bb bb bb bb bb 50% are brown, 50% are black brown brown black
Results of Cross
Phenotype
Genotype Bb Bb
brown Bb Bb
brown bb bb
black bb bb
black
50% are brown, 50% are black

37. Punnett Square Practice
A cattle breeder wants to get rid of horns in his cattle herd. Polled (no horns) is a dominant trait. Horned is recessive. If he bred a heterozygous bull to heterozygous cows would he get all polled calves? Set up an Punnett Square and answer the question. ? = X

38. h H H HH Hh Hh hh h Hh Hh H = polled h = horns
One parent is heterozygous horned Hh h H H HH Hh Hh hh h

39. HH HH Hh Hh Hh Hh hh hh 75% are polled, 25% are horned polled polled
Results of Cross
Phenotype
Genotype HH HH
polled Hh Hh
polled Hh Hh
polled hh hh
horned
75% are polled, 25% are horned

41. Incomplete Dominance X =
Some traits are not dominant or recessive
These traits will blend when heterozygous
You can use a Punnett square and will have 3 genotypes instead of two X =

42. Punnett Square Practice
In purple people eaters one eye is homozygous dominant, two eyes is homozygous recessive, and three eyes is heterozygous. The number of eyes in an incomplete dominant trait. What would the offspring look like from a homozygous recessive purple people eater and a homozygous dominant purple people eater? Set up a Punnett Square and find the genotypes and phenotypes of the offspring.

43. E E e Ee Ee Ee Ee e EE = one eye ee = two eyes Ee = three eyes
One parent is homozygous dominant
One parent is homozygous recessive EE ee E E e Ee Ee Ee Ee e

44. Ee Ee Ee Ee Ee Ee Ee Ee 100% three eyed 3 eyes 3 eyes 3 eyes 3 eyes
Results of Cross
Phenotype
Genotype Ee Ee
3 eyes Ee Ee
3 eyes Ee Ee
3 eyes Ee Ee
3 eyes
100% three eyed

46. Polygenic Inheritance
Some traits are controlled by more than one gene
There are more than 2 phenotypes
eye color
blood type
skin color
height

47. Genetic Mutations Gene undergoes a change
An error in the copying of the DNA
Some mutation are beneficial
Some mutation are harmful

48. Chromosome Disorders
Sometimes the incorrect number of chromosomes occur
This is produced by mistakes during meiosis
A change in the total number of human chromosomes (46) usually leads to death before the baby is born
However, some additions and subtraction in the chromosome number do survive

49. Down’s Syndrome
Extra chromosome at pair 21

50. Environmental Factors
The environment can effect how your genes are expressed
Genes for height but not enough food
Genes for thin but too much food