Genetics: Phenotype and Genetic Expression

Phenotype

Genetic Expression

• The phenotype is the physical and behavioral expression of an organism's genotype (genetic makeup)
• It results from the interaction between the genome and the environment
• Genetic expression is the process by which the information encoded in an organism's DNA is converted into a functional product, such as a protein
• This process involves transcription (conversion of DNA to RNA) and translation (conversion of RNA to protein)

Physical Characteristics

• The phenotype includes all physical characteristics of an organism, such as:
  • Morphology (shape and structure)
  • Anatomy (internal organization)
  • Physiology (functions and processes)
• Examples of physical characteristics:
  • Height, weight, eye color, skin color, etc.
  • Shape and size of organs, limbs, and other body parts
  • Ability to move, respond to stimuli, and perform various functions

Trait Inheritance

• The phenotype is influenced by the genotype, which is determined by the genetic information inherited from parents
• Traits are inherited in a predictable manner, according to the laws of Mendelian inheritance:
  • Autosomal dominant traits: one copy of the dominant allele is enough to express the trait
  • Autosomal recessive traits: two copies of the recessive allele are needed to express the trait
  • X-linked traits: traits influenced by genes on the X chromosome
• The expression of a trait can be influenced by environmental factors, such as:
  • Nutrition
  • Climate
  • Disease
  • Exposure to toxins

Phenotype

Genetic Expression

• Genetic expression is the process by which genetic info in DNA is converted into a functional product, such as a protein
• This process involves two stages: transcription (DNA to RNA) and translation (RNA to protein)
• Phenotype results from the interaction between the genome and the environment
• Genotype (genetic makeup) determines the phenotype

Physical Characteristics

Morphology and Anatomy

• Morphology refers to the shape and structure of an organism
• Anatomy refers to the internal organization of an organism
• Examples of physical characteristics include:
  • Height
  • Weight
  • Eye color
  • Skin color
  • Shape and size of organs
  • Shape and size of limbs and other body parts

Physiology

• Physiology refers to the functions and processes of an organism
• Examples of physiological characteristics include:
  • Ability to move
  • Ability to respond to stimuli
  • Ability to perform various functions

Trait Inheritance

Laws of Inheritance

• Traits are inherited in a predictable manner, according to the laws of Mendelian inheritance
• Autosomal dominant traits:
  • One copy of the dominant allele is enough to express the trait
• Autosomal recessive traits:
  • Two copies of the recessive allele are needed to express the trait
• X-linked traits:
  • Traits influenced by genes on the X chromosome

Environmental Influences

• Environmental factors can influence the expression of a trait, including:
  • Nutrition
  • Climate
  • Disease
  • Exposure to toxins

Explore the relationship between an organism's genotype and its physical and behavioral traits, including genetic expression and the processes of transcription and translation.