1. Genetics
Biology – S2

2. Introduction video
Also on H: Drive

3. Some of Mendel’s pea traits he work with * FATHER OF GENETICS
Mendel tested all 34 varieties of peas available to him through seed dealers. The garden peas were planted and studied for eight years. Each character studied had two distinct forms, such as tall or short plant height, or smooth or wrinkled seeds. Mendel's experiments used some 28,000 pea plants.
Some of Mendel’s pea traits he work with
* FATHER OF GENETICS

4. Conclusions from Mendel's work
1) Individual factors control each trait (genes) the different forms a gene can take are called (alleles)
2) Principal of Dominance- some factors are dominant over others, which are called recessive
The Monohybrid Cross- Mendel was curious as to what would happen if you crossed 2 different pea plants with contrasting traits

5. 3) Law of Segregation- during gamete formation alleles are separated and each gamete carries only a single copy of each gene.
"Peas Out"
Mendel also wanted to know what happened to the recessive alleles? Had they disappeared? Were they still present in the F1 plants?

6. Purebred- 2 of the same alleles for a trait (Homozygous) Homo=same
Some Genetics Terminology necessary to understanding key concepts
Purebred- 2 of the same alleles for a trait
(Homozygous) Homo=same
Hybrid- 2 different alleles for a trait
(Heterozygous) Hetero=different
Allele- different forms a gene can take
Gene- part of a chromosome with DNA information
Genotype- the genetic make-up of an organism, letters
Genotypic Ratio- ratio, in numbers, of the possibilities of a genetic cross
Phenotype- the physical characteristics of the possibilities of a genetic cross, what they look like
Phenotypic Ratio- ratio, in numbers, of the different phenotypic possibilities

7. Independent Assortment
After discovering the Principal of Segregation, Mendel wondered if gametes did so independently or did the traits have a tendency to be passed on together. It does matter if they are on the same chromosome however.
R-smooth is dominant over
constricted r
Y-yellow is dominant over green g
Two-factor Cross
Dihybrid Cross
He crossed two traits: shape and color

8. FOIL - gametes can be created by this method
Gamete production in a two factor cross
FOIL - gametes can be created by this method
F-first 1&3
O-outside 1&4
I-inside 2&3
L-last 2&4
S s Y y

9. Other methods of inheritance-important exceptions to Mendel's discoveries
Incomplete Dominance- 2 or more alleles influence the phenotype of the offspring
-flower color
-like mixing colors

10. Co-dominance- both alleles are expressed in offspring
- human blood types
- coat colors in some mammals
- checkered chickens
-sickle cell disease
Red Roan
HR x HW
HRW

12. ABO BLOOD TYPING:
Blood type AB is
the most dominant
Blood type O is the
most recessive

13. 1) A man with heterozygous B type blood marries a women with heterozygous A blood. What are the chances of them having children with type A blood? __________, Type B blood? _____________, O type blood? _____________.
2) Determine the possible blood types from the mating of a person who is homozygous A blood type and a person who is heterozygous B blood type.
3) At a local hospital, Mr. and Mrs. Lump had a child at the same time as Mr. and Mrs. Bump. The Lumps had a boy and called him Bill, while the Bumps also had a boy and called him Tony. A few weeks past and the Bumps claimed the babies were switched. They sued the hospital and all 6 individuals were asked to get their blood tested. The results of the tests were: Mr. Lump had A type blood, his wife had B type blood, and Bill had A type blood. Mr. Bump tested for O type blood, his wife had AB blood, and Tony had O type blood. Was there a switch? _________.

14. Genetics and Probability
Probability- the likelihood that a particular event will occur
Rules
1 you only get the expected outcome with large number of trials
2 previous events don't affect future results
3 independent events happening at the same time is a product of their probabilities- Product Rule
Flipping coins- having children- it's all the same!

15. Meiosis Overview

16. Diploid- (2n) refers to a complete set of chromosome (46 in humans)
Polyploid
Polyploid
Tetrad &
Crossing over
Diploid
Diploid
Haploid
Diploid- (2n) refers to a complete set of chromosome (46 in humans)
Haploid- (n) refers to ½ the normal set of chromosomes (human 23)
Polyploid

17. Meiosis- division of germ cells to create sex cells
Spermatogenesis- creation of sperm cells in the male testes
Adult males can produce
approximately 100
million sperm cells/day

18. Polar Bodies are never fertilized
Oogenesis- creation of egg cells in the female ovaries derived from germ cells
Polar Bodies are never fertilized

19. The copies then must be separated & sorted into two sides of the cell.
Mitosis vs. Meiosis
Mitosis:
If a cell wants to make a duplicate of itself, it first must copy its DNA (part of a chromosome).
The copies then must be separated & sorted into two sides of the cell.
The cell then splits in two. Part of each parent is carried to the two new cells.
Results in cells such as internal organs, skin, bones, blood, etc.
Meiosis:
As in mitosis, if a cell wants to make a duplicate of itself, it first must copy its DNA (part of a chromosome).
occurs in reproductive cells or gametes (sperm, eggs,).
Part of each parent is carried to the four new cells.

21. Meiosis Terminology:
Homologous chromosomes- pair of identical chromosomes (code for the same genes)
Diploid (2N)- full set of chromosomes (46 chromosomes)
Haploid (N)- ½ set of chromosomes (23 chromosomes)
Tetrad-a pair of chromatids (4 chromosomes total)

22. Label the following structures: centrioles, nuclear membrane, spindle fibers, centromeres, tetrads

23. Prophase I Tetrads form
centrioles
spindle fiber
aster
fibers
Tetrads form
Crossing over (exchange of genetic material) occurs

24. Crossing over Tetrad nonsister chromatids variation
chiasma: site of crossing over
variation

25. Metaphase I Tetrads align on the metaphase plate.
INDEPENDENT ASSORTMENT OCCURS:
1. Orientation of homologous pair to poles is random = genetic variation
metaphase plate
metaphase plate OR

26. Anaphase I
Spindle fibers pull homologous chromosomes apart

27. Telophase I Each pole now has diploid set of chromosomes.
Cytokinesis occurs and two diploid daughter cells are formed.

28. Meiosis II Prophase II No interphase II
(or very short - no more DNA replication)
same as prophase in mitosis

29. Metaphase II
same as metaphase in mitosis
metaphase plate

30. Anaphase II
same as anaphase in mitosis
sister chromatids separate

31. Telophase II
Remember: four haploid daughter cells are produced.

32. Meiosis Overview

33. How does meiosis create genetic variation?
Crossing over- Prophase I, homologous chromosomes exchange pieces of genetic material
Independent assortment of chromosomes- Metaphase I, tetrads line up in the middle at random
Mutations- a change in genetic information
Deletion
Duplication
Inversion
Translocation
Insertion

34. Sex Chromosomes are located at the end.
Human Heredity- recent technological advances have let humans learn more about their inheritance than ever before.
Examples: New high power microscopes, Human Genome project, gene mapping, karyotypes, and 23andme
Karyotype- a picture is taken of a cell in mitosis, where the chromosomes are condensed and they cut them and arrange into pairs
46 Chromosomes
Sex Chromosomes are located at the end.
46XX is female
46XY is male

35. Non-disjunction- failure of chromosomes to separate properly during meiosis (AKA: meiosis gone bad)

36. Genetic Disorders Video

37. Autosomal (genetic chromosomes) Non-disjunction Disorders
Trisomy 21
Downs Syndrome
The result of an extra copy of chromosome 21. People with Down syndrome are 47, 21+. Down syndrome affects 1:700 children and alters the child's phenotype either moderately or severely:
characteristic facial features, short stature; heart defects
susceptibility to respiratory disease, shorter lifespan
prone to developing early Alzheimer's and leukemia
often sexually underdeveloped and sterile, usually some degree of mental retardation.
Down Syndrome is correlated with age of mother but can also be the result of non-disjunction of the father's chromosome 21.
Maternal Age at Delivery
Risk at Term 32
1/725 33
1/592 34
1/465 35
1/365 36
1/287 37
1/255 38
1/177 39
1/139 40
1/109 41
1/85 42
1/67 43
1/53 44
1/41 45
1/32 46
1/25 47
1/20 48
1/16 49
1/12

39. Non-disjunction of Sex Chromosomes / X-Linked Genetic Disorders
Turners Syndrome
1:5000 live births; women with Turner's have only 45 chromosomes!!! XO individuals are genetically female, however, they do not mature sexually during puberty and are sterile. Short stature and normal intelligence. (98% of these fetuses die before birth) high hairline and some webbing of the neck.

40. 47XXY Klinefelter's Syndrome
Males. Male sex organs; unusually small testes, sterile. Breast enlargement and other feminine body characteristics. Normal intelligence. Affects 1:500 to 1:1000 males
47XXY

41. How would you label these examples?

42. Sex-linked disorders- most are on X chromosome, some on Y
Royal Pedigree showing Hemophilia
Colorblindness and Hemophilia are
Recessive disorders carried on the X chromosome

43. Methods of Inheritance of Hemophilia and Colorblindness

45. Why would this scenario be very hard to come by?

46. 2. Red-Green Color-Blind:
Are You Colorblind?
Sex-Linked Traits:
1. Normal Color Vision:
A: 29, B: 45, C: --, D: 26
2. Red-Green Color-Blind:
A: 70, B: --, C: 5, D: --
3. Red Color-blind:
A: 70, B: --, C: 5, D: 6
4. Green Color-Blind:
A: 70, B: --, C: 5, D: 2