Heredity Overview and Cell Division

Heredity Overview

• Heredity is the passing of traits from parents to offspring.
• This involves the complex interplay of chromosomes, alleles, genes, and various processes like mitosis and meiosis.

Chromosomes, Alleles, and Genes

• Chromosomes are structures containing genetic material.
• Alleles are different forms of a gene.
• Genes are units of heredity, located on chromosomes, carrying instructions for traits.

Cell Division: Mitosis and Meiosis

• Mitosis is a cell division process resulting in two identical daughter cells, essential for growth and repair.
• Meiosis is a cell division process resulting in four genetically unique daughter cells, crucial for sexual reproduction.

Dominant and Recessive Traits

• Dominant traits are expressed even if only one copy of the allele is present.
• Recessive traits are expressed only if two copies of the allele are present.

Genotype and Phenotype

• Genotype refers to the genetic makeup (alleles present).
• Phenotype refers to the observable traits (physical appearance).

Reaction Range, Canalization, and Correlation

• Reaction range describes the range of possible phenotypes for a given genotype.
• Canalization refers to the tendency of development to follow a certain course, regardless of environmental influence.
• Passive, evocative, and active correlations highlight how genetic and environmental factors interact to shape development.

Epigenesis and Conception

• Epigenesis emphasizes the interaction of genes and environment in development.
• Conception is the fusion of egg and sperm, initiating the development of a new organism.

Twins: Monozygotic (MZ) and Dizygotic (DZ)

• Monozygotic twins (MZ) originate from a single fertilized egg, sharing identical genetic material.
• Dizygotic twins (DZ) originate from two separate fertilized eggs, sharing about half their genetic material.