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PinkMonkey Online Study Guide-Biology Reasons for Mendel’s success:
i. Mendel concentrated on the
results of one trait at a time.
ii. When the behavior of one trait was established,
only then he considered two
characters together.
iii. He conducted a large number of crosses (2000-3000)
to eliminate the chance factor
and to obtain a valid and accurate
explanation
iv. Most of all, he actually counted the number
of offsprings of each category
and maintained accurate records for each generation
in each experiment.
v. However, luck played a major role in his success
(though Mendel did not know
this fact) in the selection of pea plants
as well as in the selection of those particular seven pairs
of contrasting characters. Because, luckily for Mendel,
in each pair, one form of the character is completely
dominant over the other. Moreover, these seven
characters are present on seven different chromosomes
in the pea plant. However, Mendel was unaware
of this fact.
In nature, there are several instances of incomplete
dominance also. In such cases, the hybrid shows haracter intermediate
between the two parents. For example, in snapdragon, when a parent
plant with red flowers is crossed with another having white flowers, the
F1 hybrids show pink flowers.
Parents
Red Flower X
White Flower
¯
F1 hybrid
Pink Flowers
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Table of Contents 7.0 Introduction
7.1 Gregor Mendel
7.2
Mendel's Experiment on Sweet Pea
7.3
Terminology Used
7.4
Law of Dominance
7.5
Monohybrid Ratio
7.6
Law of Segregation
7.7
Dihybrid Ratio
7.8
Law of Independent Assortment
7.9
Test Cross or Back Cross
7.10
The Concept of "Factor"
Chapter 8
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