5Gregor Mendel As discussed last class, he was an Austrian monk He worked at St. Thomas MonasteryHe studied both mathematics and botany
6Why did he actually Succeed? He chose the appropriate organism to studyHe designed and performed his experiments correctlyAnalysis of the data was done properly
7The Patient The common ______ also known as Pisum sativium It was chosen for 4 reasonsIt was _________ availableEasy to _____and matureThe sex organs are entirely ________ in the flowerDifferent varieties had different ________
9Purebred 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
10How 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 timeHe selected from the ________, only the plants that had the trait that he was looking forHe then bred them together (________) and then he continued this for several generations until no more of the other trait showed up
11What happened Next?He repeated this for all the other traits until he had pure bred plants with each trait.
12The 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 plantThe offspring were of course the F1 generation and he also denoted them as __________
13That F1 Generation What do you think he saw? What was the phenotype of the plants?____________________________What is this type of crossing called?
14CreativelyCreatively the name given to this type of cross is _____________It is a _______ cross between two purebred plants giving us a hybrid species
16That’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
17Terms___________________ (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
19Lets back trackYesterday we looked at the different combinations of alleles that an individual can haveWe also talked about dominance and recessivenessWhat did we say the dominant allele was?What about the recessive allele
20What were the parents?The parent that was tall had a double _______ alleleThe parent that was short had a double _______ alleleBoth of these parentswere homozygous
21When he CrossedWhen the parents were crossed, the F1 generation was completely ____________They all expressed the dominant trait, but why?__________________________________________________________
22So the First cross is done, what about the second?
24Mendelian RatioAs 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 _________________
25Based 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
26Why 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 presentThe recessive factors will be expressed ___ if the recessive factors are present
27The first Law of heredity His results gave rise to his first lawThe law of Segregation
28The law of segregationHis 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
31What 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 offspringThey also tell us something about the __________ (the appearance of a trait in an organism)
32So 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?
33F1 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 geneWhat about the genotype ratio?_______________________________________________________________________________________