- The law of independent assortment (article)
- A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed the resulting genotypes were in the ratio of
- A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed, the resulting genotypes were in the ratio of .
The law of independent assortment (article)
Let's look at a concrete example of the law of independent assortment. Imagine that we cross two pure-breeding pea plants: one with yellow, round seeds ( YYRR) and one with green, wrinkled seeds ( yyrr). Because each parent is homozygous, the law of segregation tells us that the gametes made by the wrinkled, green plant all are ry, and the gametes made by the round, yellow plant are all RY. That gives us F 1 \text F_1 F 1 start text, F, end text, start subscript, 1, end subscript offspring that are all RrYy. The allele specifying yellow seed color is dominant to the allele specifying green seed color, and the allele specifying round shape is dominant to the allele specifying wrinkled shape, as shown by the capital and lower-case letters. This means that the F 1 \text F_1 F 1 start text, F, end text, start subscript, 1, end subscript plants are all yellow and round. Because they are heterozygous for two genes, the F 1 \text F_1 F 1 start text, F, end text, start subscript, 1, end subscript plants are called dihybrids ( di- = two, -hybrid = heterozygous). A cross between two dihybrids (or, equivalently, self-fertilization of a dihybrid) is known as a dihybrid cross. When Mendel did this cross and looked at the offspring, he found that there were four different categories of pea seeds: yellow and round, yellow and wrinkled, green and round, and green and wrinkled. These phenotypic categories (categories defined by observable traits) appeared in a ratio of approximately ...
A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed the resulting genotypes were in the ratio of
A cross between pure breeding tall (TT) and dwarf (tt) plants produce all tall (Tt) plants in F 1 progeny. These heterozygous tall plants produce 50% gametes with "T" allele and 50% with "t" allele. Random fusion of these gametes from two heterozygous tall plants gives tall and dwarf plants in 3:1 ratio. out of 3/4 tall plants; 1/4 are homozygous tall (TT) and 2/4 are heterozygous tall (Tt). This makes the genotypic ratio for F 2 generation as 1 homozygous tall (TT): 2 heterozygous tall (Tt): 1 homozygous dwarf (tt). This makes option B incorrect and option A correct. Option D is incorrect as 3/4 plants are tall while 1/4 are the dwarf in F 2 generation. Option C is incorrect as the question is asking the genotypic ratio. The correct answer is A. If we cross pure-bred tall (dominant) pea plant with pure-bred dwarf (recessive) pea plant we will get Pea plant of F 1 generation, then we obtain Pea plants of F 2 generation. (a) What do the plants of F 1 generation look like? (b) State the ratio of tall plants to dwarf plants in F 2 generation. (c) State the type of plants not found in F 1 generation but appeared in F 2 generation, mentioning the reason for the same.
A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed, the resulting genotypes were in the ratio of .
Mendel crossed pure tall plant(TT) with a pure dwarf plant(tt). In the F1 generation, tall plants are formed(Tt). When F1 plant is subjected to self pollination, in the F2 generation, 3 tall plants and 1 dwarf plants are formed. In the one homozygous tall plant (TT), 2 heterozygous tall plants(Tt), one homozygous dwarf plant(tt) are formed. Phenotypic ratio is 3:1, genotypic ratio is 1:2:1. So, the correct option is ‘1:2:1 – tall homozygous:tall heterozygous:dwarf’.
