Who was Gregor Mendol?
A geneticist who primarily worked with pea plants.
Because there was a wide variety of pea plants available with easily identifiable traits.
- seed shape, seed color, height, etc.
- variety of plants that had slight variances but could be breed together.
What does a perfect flower mean?
male and female parts in the flower.
What are the male parts of the flower?
What are the female parts of the flower?
Stamen: anther and filament- produces the pollen.
Carpel: stigma, style, ovary- receives the pollen
What are the means in which a flower can reproduce?
Selfing: the pollen from one flower to fertilize eggs of that flower or different flower within that same plant.
- over many generations results in a true breeding line.
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Cross feralization: occurs when you take pollen from one plant and use that to fertilize the eggs of an entirely different plant.
What is a true breeding line?
line that allows exhibits a particularly interesting trait.
via selfing.
How did Mendel have his pea plants reproduce.
- Dude did it manually.
- Manual outcross: pick up pollen on plant with a fine tip brush and manually insert that on anther plant’s carpel structure.
What experiment did Mendel use reciprocal crosses for and what was he trying to prove?
- What is a reciporcal cross?
- talk about the experiment he used, don’t waste time mastering it just understand what the point it.
Reciprocal cross: when do crosses between…idk like sativa and Indica ( strands).
1st: dad is sativa and mom is Indica, then
2nd: dad is indica and mom is sative.
- Both must be of true breeding lines.
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For example:
1.) trait of interest is seed shape: round vs wrinkled.
2.) initially, he took pollen from a true breeding male plant who always generated round seed.
3.) He used that male plants pollen to fertilize the carpels of female true breeding plant, who always produced wrinkled seeds.
4.) Then he ran the bitch in reverse, and took pollen from a true breeding male who only generated winkled seeds.
5.) then used that pollen to fertilize the carpels of anther true breeding plant who only produced round seeds.
—————————————————————————-
- Findings: results of both reciprocal crosses were identical.
- no matter which parent gave the round seed trait it was always what their offspring contained.
- Round seed always appeared.
What does reciporcal crossing suggest?
- it doesn’t matter where the genetic determinant originates from (pollen or egg), each gamete had equal drive in the offspring genotype.
What was Medel’s second experiment and what did it test?
- What did it prove?
- Tested the blending hypothesis of inheritance: ( not wrinkled slightly wrinkled seeds like the reciporcal crossing predicts.)
- Null: one dominant trait.
- we are crossing two breeding lines of plants: round vs. wrinkled seeds.
- cross the plants again and watch for the results after the next two generations.
- takes male pollen of a round seed generator and pollenates a female plant generates wrinkled seeds.
- off spring, or F1 generation is all round seeds.
- The F1 generation is breed amongst itself, or heterozygote x heterozygote…
- generating 25% - wrinkled and 75% - round of the next gen: F2
- )
- round seed was dominant
- and the genotype of F1 was predominantly heterozygous.
What was the hypothesis of reciporcal crossing, what was the null?
- one of the two traits present would dominate over the over.
Null (blending hypothesis): the product of the reciporcal crossing led to a heterogenous individual. i.e. slightly wrinkled seed shape.
What does true breeding lines result in?
- homozygous, two identical alleles for the gene that encodes a specific trait.
What is progeny?
- context clues makes me think offspring.
What is heterozygous progeny?
Offspring have two different alleles encoding for different traits
What is a monohybrid cross?
- essentially make a punnet sqaure for two individuals that are heterozygous for the same trait.
- Which results in 25% homozygous dominant.
- 25% homozygous recessive
- 50% heterozygous .
What were Mendel’s claims?
What were the modern day responses?
- pea plants must have two copies of each gene making it possible to for any one pea plant to have two different alleles.
- This is true for many other organisms
- Genes are discrete particles of inheritance, they don’t get modified from one generation to the next.
- genes do not change when being transmitted between generations.
- Each gamete contains one copy of each gene.
- This is due to principle of segregation- the members of each pair segregate during the formation of gametes.
- males and females equally contribute to the inheritance of their offspring.
- When gametes fuse, offspring acquire a total of two of each gene- one from each parent.
- some alleles are dominant to others.
- When a dominant and recessive allele for a gene are paired in a heterozygote, that individual has the dominant phenotype.
Describe Mendel’s experiment where he tested inheritance of traits encoded by two different genes?
( seed shape and seed color)
- what were the possible outcomes in his mind?
- Don’t say results/findings of experiment:
- he tested two hypothesis, round vs. wrinkled seeds and green vs. yellow seeds.
- round and yellow were dominant.
- —————————————————————————– - classic Mendel, wanted to follow these traits so he took plants of true breeding lines.
- so one true breeding type had both dominant traits in the homozygous form.
- ## the other was a true breeding type has homozygous recessive for both traits.
- if two different genes are passed on from one parent, Those genes would have to stay together in the gametes and moving forward: Dependent assortment
OR - Independent assortment: alleles of different genes don’t stay together at all, and so the genes will behave independent of one anther in the next generation.
What is dependent assortment?
if two different genes are passed on from one parent, Those genes would have to stay together in the gametes moving forward.
What were the hypothesis that Mendel tested in his experiment testing inheritance of traits encoded by two different genes?
- dependent assortment hypothesis.
- independent hypothesis assortment
What is independent assortment?
chapter 14 vid 2, 4:00
- the alleles of different genes don’t stay together what so ever, thus allowing them to behave totally independent of one anther in the next gen.
9 : 3 : 3 : 1 ratio brother
In regards to Mendel actually testing the independent vs. dependent hypothesis, how did he conduct this experiment?
- He crossed true breed recessive plants with true breeding dominant plants.
- Which resulted in their offspring (F1) being Dihybrid: one dominant and one recessive allele, that Mendel was interested in.
- Next 2.) he crossed the dihybrid individuals (F2), which yielded an F2 generation that resulted in alleles of different genes not staying together.
- independent assortment is true.
What is dihybrid cross?
F1 X F1
Or
heterozygous x heterozygous.
What happens if two genes are present of the same chromosome?
- will they still exhibit independent assortment?
- Thomas Hunt Morgan and his group went about testing this with fruit flies.
- basically recombinant genes occur in tiny percentages.
- you also see a variety of independent and dependent assortment.
Who is Thomas Hunt Morgan?
- what did he study.
- Describe his experiment?
- Geneticists who studied the sex-linked inheritance of Drosophila, in particular…
- his group was focused on finding genes found on the sex chromosome of Drosophila.
- The fruit flies have ( X.X = Female) and (X.Y = male)
- therefore, half of the male fruit flies sperm will contain an X and the other half will contain a Y chromosome.
- He tested if genes on the same chromosome exhibited dependent or independent assortment.
What does a difference in the male offspring of a reciporcal cross indicate?
- indication that the gene involved in that phenotype is on the X-chromsome
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Chapter 111
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Chapter 239
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CHapter 435
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Chapter 324
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Chapter 520
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chapter 613
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Chapter 6 Part 2: Membrane Permeability13
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Chapter 6 membrane proteins:6
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Unit 20
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Chapter 6 Part from uni 224
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Chapter 828
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Chapter 7:110
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Chapter: 9: prt: 1, 2, 352
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Chapter 9 pt: 4,533
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Chapter 10 Parts 1 & 233
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Chapter 10 Parts 3 & 436
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Unit 30
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Chapter 1164
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Chapter 1548
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Chapter 1246
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chapter 1369
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chapter 1434
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chapter 14 parts 3 & 422
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chapter 14 mastering5
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Unit 4:0
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Chapter `1626
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chapter 17:31
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Chapters 1829
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chapter 1935
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Unit 5:0
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Chapter 33 Pt. 1 (overview of viruses)14
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Chapter 33 Part 2:7
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Part 311
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Part 40
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Chapter 48 Pt 1.14
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Part 210
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part 3:16
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Part 413
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Part 513
