CONCEPTS OF GENETICS WILLIAM KLUG EXAM PREPARATION PACK 2026 KEY CONCEPTS AND REVISION NOTES

CONCEPTS OF GENETICS WILLIAM KLUG
EXAM PREPARATION PACK 2026 KEY
CONCEPTS AND REVISION NOTES

◉ Mutation. Answer: A change in DNA sequence that may affect gene
function.


◉ Substitution. Answer: A mutation where one nucleotide is
replaced with another.


◉ Insertion. Answer: A mutation where an extra nucleotide is added
to the DNA sequence.


◉ Deletion. Answer: A mutation where a nucleotide is removed from
the DNA sequence.


◉ Frameshift. Answer: A mutation caused by insertion or deletion
that shifts the reading frame.


◉ Allele. Answer: A different form of a gene.


◉ Dominant. Answer: An allele that shows its trait even if only one
copy is present.

, ◉ Recessive. Answer: An allele that is only expressed if two copies
are present.


◉ Genotype. Answer: The genetic makeup of an organism (e.g., Aa,
BB).


◉ Phenotype. Answer: The physical expression of a trait (e.g., brown
eyes).


◉ Homozygous. Answer: Having two identical alleles for a trait (e.g.,
AA or aa).


◉ Heterozygous. Answer: Having two different alleles for a trait (e.g.,
Aa).


◉ Gamete. Answer: A sex cell (sperm or egg) with half the number of
chromosomes.


◉ Zygote. Answer: A fertilized egg formed by the union of two
gametes.


◉ Mendelian Trait. Answer: A trait controlled by a single gene with
dominant/recessive alleles.