Genetics and Anthropometry Lecture Notes

Cell Components
- Cell: Basic unit of life, responsible for all life processes.
  - Contains organelles like the nucleus, mitochondria, and ribosomes.
- Nucleus: Contains genetic material in the form of DNA.
  - Controls cell growth, metabolism, and reproduction.
  - Surrounded by a nuclear envelope.
- Chromosome: Structure within the nucleus carrying genes.
  - Made of DNA tightly coiled around proteins called histones.
  - Humans have 46 chromosomes arranged in 23 pairs.
- DNA: Deoxyribonucleic acid, the molecule carrying genetic instructions.
  - Double helix structure composed of nucleotides.
  - Contains the genetic code for building and maintaining organisms.
DNA Structure
- DNA:
  - Nucleosome: Basic unit of DNA packaging composed of DNA wrapped around histone proteins.
  - Nucleotide: Building block of DNA.
    - Consists of a sugar (deoxyribose), a phosphate group, and a nitrogenous base.
  - Gene: Segment of DNA that codes for a specific trait or protein.
    - Basic unit of heredity.
  - Base Pairs:
    - Guanine (G): Pairs with Cytosine (C).
    - Cytosine (C): Pairs with Guanine (G).
    - Adenine (A): Pairs with Thymine (T).
    - Thymine (T): Pairs with Adenine (A).
  - Histone: Proteins around which DNA is coiled to form chromatin.

Mitosis Defined: Process of cell division resulting in two identical diploid cells.
- Important for growth, repair, and asexual reproduction.
DNA Replication: Occurs before mitosis to ensure each daughter cell receives a complete set of chromosomes.
- Ensures genetic information is accurately passed on.

Cell Differentiation: Process by which cells become specialized for specific functions (e.g., muscle cells, nerve cells, liver cells).
- Results from differential gene expression.
Stem Cells: Undifferentiated cells with the potential to become various cell types.
- Two main types: embryonic stem cells and adult stem cells.
Stem Cells and Aesthetics: Stem cells have revolutionized burn treatment with spray-on skin technology.
- Can regenerate damaged tissues and reduce scarring.

Genetic Inheritance: One gene from each parent.
- Sperm and egg contain one set of 23 chromosomes.
  - These are called haploid cells.
- Fertilization results in 46 chromosomes (two copies of each gene).
  - Forms a diploid cell (zygote).
Genotype: Genetic makeup of an organism; instructions for growth and development.
- Determines the potential traits of an organism.
Phenotype: Observable characteristics influenced by both genotype and environment (e.g., height, weight, skin color).
- Interaction between genes and environment determines phenotype.

Genes vs. Destiny: Genes can be switched on/off by lifestyle, diet, environment.
- Gene expression can be altered without changes to the DNA sequence.
External Factors: Influence gene expression (e.g., type 2 diabetes).
- Environmental factors, lifestyle choices, and diet can modify gene expression.
Epigenetics: The study of how your behaviors and environment can cause changes that affect the way your genes work.
- Epigenetic changes can be passed on to future generations.
Epigenetics and Aesthetics: Environmental factors (e.g. UVR exposure in different countries) can trigger genes involved in skin cancer development.
- Other factors include diet, medications, workplace, and culture.

Facial Structure Components: Bone, muscle, nerves, fat, ligaments, and skin.
- These components contribute to facial shape and appearance.
Anthropometry: Measurement of human body proportions.
- Used to quantify and analyze facial features.

da Vinci's Vitruvian Man: Concept of ideal human body proportions.
- First anthropometric measurements made famous.
Beauty: Subjective, possibly a formula, in the eye of the beholder or a combination.
- Different cultures and individuals may have varying perceptions of beauty.
Max Factor: Historical approach to measuring beauty.
- Developed makeup and techniques to enhance facial features.
Phi (Golden Ratio): Mathematical concept (1.618) applied to nature and man-made objects.
- Dr. Marquardt's Beauty Mask.
- $(\text{Golden Ratio} = 1.618)$

Horizontal Facial Proportions: Divided into thirds.
- Forehead, nose, and lower face.
Vertical Facial Proportions: Divided into fifths.
- Eye width used as a unit of measurement.
Facial Landmarks: Upper, middle (including nose), and lower thirds.
- Used to assess facial symmetry and balance.

Facial Symmetry: Important but not perfectly symmetrical, faces can look unusual.
- Minor asymmetries are common and can add character.

Visual Assessment: Common in aesthetics.
- Relies on the trained eye of the practitioner.
Hinderer’s Lines: From mouth corner to eye corner, intersected by a line from nose corner to tragus; filler placed in upper outer quadrant (not universal).
- Used for guidance in filler placement.
Ricketts Line (E-Line): From nose tip to chin; used in orthodontics and cosmetic surgery.
- Assesses the balance of the profile.

Measuring Tools
Errors and Variables: Measurements depend on the measurer; variables in facial structure; not a universal rule.
- Individual variations and ethnic differences must be considered.

Measuring Beauty: Phi, horizontal thirds, vertical fifths, symmetry.
- These are guidelines, not strict rules.
Aesthetics: