In chromosomal analysis, the organized image of all chromosomes from a cell is called a karyotype. A karyotype shows the number and appearance of chromosomes, typically arranged in pairs by size and banding pattern, and is prepared from cells arrested in metaphase and stained to reveal characteristic bands. This visual snapshot allows scientists to detect abnormalities such as extra or missing chromosomes, translocations, or structural changes. The other terms don’t fit as well: a genome refers to the entire set of genetic material, not a single chromosomal image; chromosome count is just the total number of chromosomes and doesn’t capture their size or structure; and a nucleoid image describes bacterial DNA organization, not the eukaryotic chromosome arrangement used in standard chromosomal analysis.

Two genes with independent assortment and complete dominance produce a dihybrid phenotypic pattern. For each gene, Aa x Aa gives a 3:1 phenotypic split (dominant to recessive). Because the two genes assort independently, multiply the probabilities for combined phenotypes. - Dominant for both traits: 3/4 × 3/4 = 9/16 - Dominant for one trait, recessive for the other: 3/4 × 1/4 = 3/16 (two such cases) - Recessive for both traits: 1/4 × 1/4 = 1/16 Putting these together gives a 9:3:3:1 phenotypic ratio. This is the classic result for a dihybrid cross under independent assortment and complete dominance.

Loss of genetic material from a chromosome is called a deletion. This mutation means all or part of the chromosome is missing, so fewer genes are present in that region. Deletions can occur at the end of a chromosome (terminal) or within the chromosome (interstitial), and they can have significant effects depending on which genes are lost. In contrast, duplications add extra copies of a chromosome segment, inversions flip a segment's order without removing material, and translocations move a segment to a different chromosome or location. A classic example of a deletion-related condition is Cri du chat, caused by a missing piece of chromosome 5.

Incomplete dominance is when the heterozygous genotype produces a phenotype that is intermediate between the two homozygous phenotypes because neither allele fully masks the other. An example uses color: red is produced by one allele, white by the other, so RR plants are red, rr plants are white, and Rr plants are pink. This shows a blending effect where the heterozygote sits between the two extremes. This differs from complete dominance, where the heterozygote looks like one of the homozygotes, and from codominance, where the heterozygote displays both traits at once (as with AB blood type having both A and B antigens).