1
Q
Mendel’s Hypothesis
A
- In the organism there is a pair of factors that controls the appearance of a given
characteristic. (We call them genes.) - The organism inherits these factors from its parents, one from each.
- Each factor is transmitted from generation to generation as a discrete, unchanging unit. (The
wrinkled seeds in the F2 generation were no less wrinkled than those in the P generation
although they had passed through the round-seeded F1 generation.) - When the gametes are formed, the factors separate and are distributed as units to each
gamete. This statement is often called Mendel’s rule of segregation. - If an organism has two unlike factors (we call them alleles) for a characteristic, one may be
expressed to the total exclusion of the other (dominant vs recessive).
2
Q
Law of Domiance
A
The law of dominance states that when two alternative forms of a trait or
character (genes) are present in an organism, only one factor expresses itself
in F1-progeny and is called dominant, while the other that remains masked is
called recessive.
3
Q
Law of Segregation
A
This law states that the alleles do not show any blending and
both the characters are recovered as such in the F2-
generation, though one of these is not seen in the F1 -
generation.
4
Q
Mendelian Inheritance
A
- This refers to traits where there are both a dominant and recessive allele present as
heterozygous pair. The dominant allele has complete control over the phenotype. - Not all traits are Mendelian traits some may be categorise as:
o Incomplete dominance
o Co dominance
o Sex linkage
o Autosomal linkage
o Epistasis
