Entrance Exams
Govt. Exams
Recessive phenotype = 360/1000 = 0.36 = q². Therefore q = √0.36 = 0.60. This represents the frequency of recessive allele.
In Hardy-Weinberg equation, p and q represent frequencies of two alleles in a population. p² and q² are homozygous frequencies; 2pq is heterozygous frequency.
The correct hierarchical order is: Nucleotide (basic unit) → DNA (polymer of nucleotides) → Gene (segment of DNA) → Chromosome (condensed DNA with proteins).
The 1:1 ratio indicates a testcross result (Rr × rr). The round seed parent must be heterozygous (Rr) to produce wrinkled (rr) offspring.
AA × aa produces all Aa offspring (test cross principle). All offspring are heterozygous with dominant phenotype.
Alleles are alternative forms of a gene that occupy the same locus on homologous chromosomes and control different variations of the same trait.
Monohybrid cross Aa × Aa produces genotypic ratio 1 AA : 2 Aa : 1 aa. Probability of aa (homozygous recessive) = 1/4 or 25%.
Mendel's Law of Segregation states that hereditary traits are controlled by discrete units (genes) that separate during gamete formation.
Humans have 46 chromosomes (23 pairs) in somatic cells - 22 pairs of autosomes and 1 pair of sex chromosomes (XX or XY).
A gene is the fundamental unit of heredity that carries information for a specific trait. It consists of a segment of DNA coding for a protein or RNA.