Define the following:
(a) Polygenic
(b) Additive alleles
(c) Correlation
(d) Monozygotic and dizygotic twins
(e) Heritability
(f) QTL
(g) Continuous variation

Verified step by step guidance

1. Define (a) Polygenic: Explain that polygenic traits are controlled by multiple genes, each contributing a small effect to the overall phenotype, resulting in continuous variation rather than discrete categories.
2. Define (b) Additive alleles: Describe additive alleles as alleles whose effects on a trait sum up in a cumulative way, meaning each allele adds a certain amount to the phenotype independently of other alleles.
3. Define (c) Correlation: Clarify that correlation in genetics refers to a statistical measure that describes the degree to which two traits or variables are related or vary together in a population.
4. Define (d) Monozygotic and dizygotic twins: Monozygotic twins originate from a single fertilized egg that splits, making them genetically identical, while dizygotic twins come from two separate eggs fertilized by two different sperm, making them genetically similar like regular siblings.
5. Define (e) Heritability: Explain heritability as the proportion of phenotypic variation in a population that is attributable to genetic variation among individuals, often expressed as a value between 0 and 1.
6. Define (f) QTL (Quantitative Trait Locus): Describe QTL as a specific region of the genome that is associated with variation in a quantitative trait, identified through statistical analysis linking genetic markers to phenotypic variation.
7. Define (g) Continuous variation: Explain continuous variation as a type of phenotypic variation where traits show a range of small differences across a population, often influenced by multiple genes and environmental factors, producing a smooth distribution of phenotypes.

Key Concepts

Polygenic

Polygenic refers to a trait controlled by multiple genes, each contributing a small effect to the phenotype. Unlike single-gene traits, polygenic traits show continuous variation, such as height or skin color, because the combined influence of many genes produces a range of outcomes.

Additive Alleles

Additive alleles are gene variants whose effects sum up to influence a trait. Each allele contributes a certain amount to the phenotype, and the total effect is the sum of all alleles involved, explaining gradual differences in traits like weight or intelligence.

Heritability

Heritability measures the proportion of phenotypic variation in a population that is due to genetic differences among individuals. It ranges from 0 to 1 and helps determine how much genetics versus environment influences a trait.