Answers
Explanation:
A cross between two types of plants of same species considering only the transmission of one character is called monohybrid cross. For example, a cross between tall pea plants and dwarf pea plant that is considering only the height of the parents is a monohybrid cross. It will result in the formation of tall offsprings but they will be hybrid.
Representation of the monohybrid cross: character in focus is the height
Parents- TT X tt
(Tall) (dwarf)
F1. Tt
(Heterozygous tall)
On selfing:
Tt X tT
F2. TT Tt Tt tt
Phenotypic ratio-
3 tall: 1 dwarf
Genotypic ratio-
1 homozygous tall: 2 heterozygous tall: 1 homozygous recessive
Example
F1-generation plants
Mendel crossed SS (spherical seeds) with ss (dented seeds.)
All of the gametes of the spherical seeded parent have the S (dominant) allele and all of the gametes of the dented seeded parent have the s (recessive) allele. All of the F1 generation plants will have the genotype of Ss (heterozygous), and all will be spherical seeded.
F1 generation
=
F2-generation plants
Mendel let the F1-generation plants self-pollinate to form a second generation and he analyzed the seeds of the resulting F2 generation.
F2 generation
=
All F1-hybrid plants have the genotype Ss and all are spherical (dominant characteristic). The recessive alleles segregate during gamete formation. As a result, one out of four possible combinations of F2-generation plants will have the homozygous recessive genotype (ss).