Offspring can have traits that neither parent visibly exhibits due to several genetic mechanisms:

• Recessive alleles: Each parent can carry a recessive allele for a trait without showing it themselves if they also have a dominant allele. When offspring inherit the recessive allele from both parents, the recessive trait appears in them, even though neither parent shows it. This is a classic Mendelian inheritance pattern

• Genetic recombination: During meiosis, chromosomes exchange segments (crossing over), creating new combinations of alleles that neither parent exactly has. This reshuffling can produce offspring with novel trait combinations that neither parent visibly exhibits

• Polygenic traits: Traits controlled by multiple genes (polygenic) can result in offspring having a combination of gene variants that produce a trait not clearly seen in either parent because the parents' gene combinations differ

• Non-Mendelian inheritance: Some traits follow complex inheritance patterns such as extranuclear (mitochondrial or chloroplast DNA inherited only from the mother), genomic imprinting (where gene expression depends on the parent of origin), or gene conversion during DNA repair, which can all lead to offspring traits not directly predictable from parental traits

In summary, offspring traits can differ from parents due to recessive alleles becoming homozygous, genetic recombination creating new allele combinations, polygenic effects, and complex non-Mendelian inheritance mechanisms.