1. Introduction to Genetics
Chapter 11
Introduction to Genetics
Biology 2016

2. Mitosis
The process in cell division by which the nucleus divides, typically resulting in two new nuclei, each of which contains a complete copy of the parental chromosomes
Biology 2016

3. Mitosis
Mitosis is a process of cell division which results in the production of two daughter cells from a single parent cell.
Biology 2016

4. Biology 2016

5. 4 Phases of Mitosis Prophase:
Each chromosome has duplicated and consists of two sister chromatids. At the end of prophase, the nuclear envelope breaks down into vesicles.  
Metaphase:
The chromosomes align at the equitorial plate and are held in place by microtubules attached to the mitotic spindle and to part of the centromere.  
Biology 2016

6. 4 Phases of Mitosis
Anaphase: The centromeres divide. Sister chromatids separate and move toward the corresponding poles.  
Telophase: Daughter chromosomes arrive at the poles and the microtubules disappear. The condensed chromatin expands and the nuclear envelope reappears.
Biology 2016

7. Biology 2016

8. Mitosis
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9. Biology 2016

10. Meiosis
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11. Biology 2016

12. Meiosis Meiosis involves two cell divisions: Meiosis I and Meiosis II.
Meiosis I separates the matching - or 'homologous' - pairs of chromosomes.
Meiosis II divides each chromosome into two copies (much like mitosis).
Biology 2016

13. Meiosis I
Biology 2016

14. Meiosis II
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15. Mitosis Vs. Meiosis
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16. Biology 2016

17. Biology 2016

18. Comparison
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19. Introduction into Genetics
Biology 2016

20. Introduction to Genetics
Back in 1997, a rather bizarre photograph suddenly became very famous. It showed a totally hairless mouse, with what appeared to be a human ear growing out of its back.
“Alba”, the green fluorescent bunny, is an albino rabbit. This means that, since she has no skin pigment, under ordinary environmental conditions she is completely white with pink eyes. Alba is not green all the time. She only glows when illuminated with the correct light.
Biology 2016

21. Introduction into Genetic - 2
Biology 2016

22. Genetics Gregor Mendel – “Father of Genetic”
Austrian Monk in the Czech Republic
Mendel worked in the monastery garden
Mendel worked with ordinary garden peas
Mendel studied the structure of the flowers of pea plants
Mendel observed the distinct traits of pea plants
Biology 2016

23. Biology 2016

24. Genetics
Traits: specific characteristics that can be passed from parent to offspring that varies from one individual to another
Example: the pea plant’s seed shape, color, height, flower position
Genetics: is the scientific study of heredity
Heredity: transmission of genetic traits from parent to offspring
Biology 2016

25. 3 reasons why Mendel studied genetics
Mendelian Genetics
3 reasons why Mendel studied genetics
He selected the pea because of its distinguishable traits. Example: flower color, seed color, seed shape
He knew from prior experiments that one of the traits would disappear in one generation
Plant as easy to grow
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26. Biology 2016

27. Biology 2016

28. Pea Plant Traits
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29. Pea Plant Flower
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30. Mendelian Genetics
Fertilization: the process that occurs during sexual reproduction where by male & female reproductive parts join. Fertilization produces a new cell which develops into a tiny embryo.
True-Breeding: occurs in both animals & plants where by they produce offspring identical to themselves.
Biology 2016

31. Mendel’s Experiment
Gregor Mendel studied garden peas. Pea plants are usually self-pollinating.
Self-pollination: a plant fertilizes itself.
This means that the pollen (sperm) of one plant will fertilize the egg of the same plant. The seeds produced will inherit all of their characteristics from the single plant that bore them.
These self-pollinating pea plants produced true-breeding or pure offspring. They would produce offspring identical to themselves.   
Biology 2016

32. Mendel wanted to see what would be the offspring of a tall pea plant X with a short (dwarf) pea plant. 
TT (Tall)  x tt (Short)
This is called a monohybrid cross because it only looks at the inheritance of one trait at a time.
Mendel expected to find all the offspring to be of medium height (a blending of tall and short plants.)
What Mendel found was that all the offspring were tall.
Mendel concluded that we have two factors (called genes) that control each trait. 
Biology 2016

33. Mendel concluded that we have two factors (called genes) that control each trait.   
·    Each of these genes can be expressed in different forms (alleles).  Example: tall and short
TT (Tall)  x tt (Short)
Biology 2016

34. Biology 2016

35. Mendel’s Monohybrid Cross
Mendel concluded that we have two factors (called genes) that control each trait.   
    Each of these genes can be expressed in different forms (alleles).  Example: tall and short
Biology 2016

36. Genetic Terms Gene – section of chromosome that codes for a trait
Allele – distinct form of a gene
Dominant allele – form of a gene, which is fully expressed
Recessive allele – form of a gene, which is not expressed when paired with a dominant allele
Biology 2016

37. Laws of Genetics
Law of independent assortment – each member of a pair of homologous chromosomes separates independently of the members of other pairs so the results are random.
Law of segregation – each pair of (homologous) genes separates (segregates) during meiosis.
Biology 2016

38. Laws of Genetics
Law of dominance – the dominant allele is expressed and the recessive allele can be hidden
Probability – likelihood of an event happening
Punnet Square – grid for organizing genetic material, shows probabilities not results
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39. Laws of Genetics
Monohybrid cross – studying the inheritance of only one trait at a time “cross” refers to mating between male and female
Dihybrid cross- studying the inheritance of two traits at a time
Test cross – if you don’t know if a trait expression is from genotype which is homozygous dominant or heterozygous, you cross it with a homozygous recessive so expression of recessive trait would occur if it existed
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40. Laws of Genetics
Complete dominance: when the one allele completely masked by another allele.
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41. Biology 2016