4. Mendel’s Genetics
Monohybrid Cross

5. Gregor Mendel As discussed last class, he was an Austrian monk
He worked at St. Thomas Monastery
He studied both mathematics and botany

6. Why did he actually Succeed?
He chose the appropriate organism to study
He designed and performed his experiments correctly
Analysis of the data was done properly

7. The Patient The common ______ also known as Pisum sativium
It was chosen for 4 reasons
It was _________ available
Easy to _____and mature
The sex organs are entirely ________ in the flower
Different varieties had different ________

9. Purebred What is a purebred organism?
__________________________________________________________
Why was this important to Mendel and his pea plants?
This is because he used purebred plants to conduct all of his experiments

10. How did he make sure?
How did Mendel make sure that his organisms (pea plant) were pure bred?
He bred them as everyone else bred plants, and he looked at _____ ______ at a time
He selected from the ________, only the plants that had the trait that he was looking for
He then bred them together (________) and then he continued this for several generations until no more of the other trait showed up

11. What happened Next?
He repeated this for all the other traits until he had pure bred plants with each trait.

12. The first of the Crosses
So what did he end up doing next?
He started to _______________
He designated the parents as the ____ generations and crossed a true-breeding _____pea plant, with a true-breeding ______ pea plant
The offspring were of course the F1 generation and he also denoted them as __________

13. That F1 Generation What do you think he saw?
What was the phenotype of the plants?
____________________________
What is this type of crossing called?

14. Creatively
Creatively the name given to this type of cross is _____________
It is a _______ cross between two purebred plants giving us a hybrid species

15. What did his experiment look like?

16. That’s the Phenotype We have now seen the phenotype
All of the F1 generations plants were _____
What do you think the genotype must be of the offspring?
First we have to learn some more terms

17. Terms
___________________ (TT) – Two alleles for a trait that are the same as a result of pure breeding
___________________ – Having two alleles for a trait that are different
___________________ - Two alleles for a trait that are the same as a result of pure breeding

18. The First Cross PF1
Tall
Short

19. Lets back track
Yesterday we looked at the different combinations of alleles that an individual can have
We also talked about dominance and recessiveness
What did we say the dominant allele was?
What about the recessive allele

20. What were the parents?
The parent that was tall had a double _______ allele
The parent that was short had a double _______ allele
Both of these parents
were homozygous

21. When he Crossed
When the parents were crossed, the F1 generation was completely ____________
They all expressed the dominant trait, but why?
__________________________________________________________

22. So the First cross is done, what about the second?

23. Second Cross Genotype

24. Mendelian Ratio
As Mendel completed the experiment, he found that ____of the offspring of the F1 cross were the ________ (tall) and ____ were the _______ (short)
The Ratio of _____ is known as the _________________

25. Based on observations, Why did this happen?
Each parent in his F1 Generation starts with two hereditary “factors.” One factor is _______ and the other ________
The factors separate out in the and only one of the two factors contribute to the phenotype of the offspring

26. Why did this happen?
The offspring inherit ____ factor from ____ and ____ from ____. If the dominant factor is present, it will be _______, even if the recessive one is present
The recessive factors will be expressed ___ if the recessive factors are present

27. The first Law of heredity
His results gave rise to his first law
The law of Segregation

28. The law of segregation
His law of segregation states: __________ _________________________________
These factors segregate in the gametes (after meiosis)
Mendel did not know that his factors were actually genes, we know this today

29. What do we call this?

30. Punnett Square

31. What do they do for us?
Well, they are used by geneticists so that they can _________ the expected ratio (__________) and to suggest possible combinations of _______ in the offspring
They also tell us something about the __________ (the appearance of a trait in an organism)

32. So we saw TT x tt And for that cross we ended up having a ratio of?
All were Heterozygous (100% - 0%)
What about when we cross the F1 x F1 generations?

33. F1 X F1 What’s the ratio when we are talking about phenotype?
3:1 as well, three of the offspring will present the dominant gene while the fourth will present the recessive gene
What about the genotype ratio?
_______________________________________________________________________________________

34. Example

35. Class Work Read Pages 202 -212 Complete Questions 205 #1, 5, 6