Describe the steps or procedure of mendel's experiments with suitable example.
Answers
Answer:
Gregor studied seven traits of the pea plant: seed color, seed shape, flower position, flower color, pod shape, pod color, and the stem length. There were three major steps to Mendel's experiments:
1. First he produced a parent generation of true-breeding plants. He made these by self-fertilizing the plants until he knew they bred true to the seven traits. For example, the purple flowering plants always produced seeds that made purple flowers. He called these plants the P generation (for parent).
2. Next, he produced a second generation of plants (F1) by breeding two different true-breeding P plants.
3. He then produced a third generation of plants (F2) by self-pollinating two F1 generation plants that had the same traits.
Mendel's Results
Mendel found some incredible results from his experiments.
F1 Generation
Mendel found that the F1 generation all produced the same trait. Even though the two parents had different traits, the offspring always had the same trait. For example, if he bred a P plant with a purple flower with a P plant with a white flower, all of the offspring (F1) plants would have purple flowers. This is because the purple flower is the dominate trait.
These results can be shown in a diagram called a Punnett square. The dominate gene is shown with a capital letter and the recessive gene with a lower case letter. Here the purple is the dominant gene shown with a "P" and the white is the recessive gene shown with a "w."
PPwPwPwwPwPw
You can go to this page to learn more about inheritance patterns and Punnett Squares.
F2 Generation
In the F2 generation he found that 75% of the flowers were purple and 25% were white. Even though both parents had purple flowers, 25% of the offspring had white flowers. This turned out to be because of a recessive gene or trait was present in both parents.
Here is the Punnett square showing that 25% of the offspring had two "w" genes causing them to have white flowers:
Answer:
Mendel selected true breeding tall (TT) and dwarf (tt) pea plants.When a tall pea plant is crossed with a short (dwarf) pea plant, all the F1 hybrids are tall. (i.e., in this case, the gene causing tallness is dominant while the gene causing dwarfness is recessive.).The trait expressing itself in the hybrid is the dominant one.
(Mendel’s first law of inheritance states that when a pair of contrasting factors is brought in a hybrid, one factor inhibits the appearance of the other. The one which inhibits is the dominant one and which is inhibited is recessive.)
In Mendel’s experiment of breeding tall (TT) and dwarf (tt) plants, Mendel found that all plants in the F1 generation were tall.
The F1 generation had genetic constitution Tt. It is genotypically a hybrid and a heterozygous plant having two different alleles, T and t.
Phenotypically, the plant is tall because the allele or the gene T for tallness masks the effect of its corresponding recessive gene t.
So, dwarf plants with genotype (tt) were not obtained in the F1 generation. This implies that out of two, one of the contrasting characters for a particular trait is dominant which masks the expression of the other character which then becomes recessive.
This experiment showed that traits may be dominant or recessive, depending on their expression in the F1 generation.