In the following table, average differences of height, weight, and fingerprint ridge count between monozygotic twins (reared together and apart), dizygotic twins, and nontwin siblings are compared:   Trait            MZ Reared    MZ        DZ Reared   Sibs Reared                     Together      Reared     Together       Together                                          Apart                                              _Height (cm)      1.7              1.8             4.4                4.5 Weight (kg)      1.9               4.5            4.5                4.7 Ridge count     0.7               0.6            2.4                 2.7 Based on the data in this table, which of these quantitative traits has the highest heritability values?

Key Concepts

Heritability

Heritability is a measure that estimates the proportion of variation in a trait that can be attributed to genetic differences among individuals in a population. It is expressed as a value between 0 and 1, where 0 indicates no genetic contribution and 1 indicates complete genetic determination. Understanding heritability helps in assessing the extent to which genetics influence traits like height, weight, and fingerprint ridge count.

Monozygotic vs. Dizygotic Twins

Monozygotic (MZ) twins originate from a single fertilized egg and share nearly identical genetic material, while dizygotic (DZ) twins come from two separate eggs and share about 50% of their genes, similar to regular siblings. Comparing traits between MZ and DZ twins allows researchers to infer the genetic versus environmental contributions to those traits, as MZ twins are expected to show more similarity due to their shared genetics.

Quantitative Traits

Quantitative traits are characteristics that can be measured and quantified, such as height, weight, and fingerprint ridge count. These traits typically exhibit continuous variation and are influenced by multiple genes and environmental factors. Analyzing the differences in these traits among various sibling types helps in understanding the genetic basis and heritability of these traits.