D3.2 Inheritance

Gametes with 1 copy of each chromosome, produced by meiosis; fuse to form diploid zygote.

Same size, banding, centromere, genes at same loci; may have different alleles.

Allele = version of a gene; Genotype = allele combination; Phenotype = observable trait.

Homozygous = same alleles; Heterozygous = different alleles; Hemizygous = only 1 allele (e.g., male X-linked).

P = pure-breeding parents; F1 = offspring of P; F2 = offspring of F1 self-cross.

Assign alleles (dominant uppercase), write gametes, fill grid, determine genotypes & phenotypes.

Mono = 1 gene, dihybrid = 2 genes (independent assortment).

Dominant expressed in homozygous/heterozygous; recessive only in homozygous.

Mouse coat: B = black (dominant), b = light (recessive).

Autosomal recessive; mutation in PAH gene → phenylalanine accumulates → brain damage.

X-linked recessive; males affected, females carriers; defective clotting factor gene on X.

More than 2 alleles in gene pool; individual inherits 2.

Heterozygote shows intermediate trait (e.g., Mirabilis jalapa flowers: red × white → pink).

IA & IB codominant, i recessive.

XX = female, XY = male; sperm determines sex.

Affected father → all daughters affected. Affected mother → sons affected, daughters may be carriers.

Continuous = polygenic/environment (e.g., skin color); Discrete = single gene (e.g., ABO).

Trait changes via gene expression in response to environment (e.g., snail shell shape).

Shows min, max, median, Q1, Q3, outliers (1.5 × IQR).