2026-03-28 21:22

Status: #new

Tags: #biology #genetics

Genetic Mutations

• There are 2 types of Genetic Mutation
  • Errors in Meiosis
  • Change in Chromosome Structure

Errors in Meiosis

• Improper distribution during cell division
• When the process of genetic division occurs improperly, it is appropriately named, "non-disjunction".
  • Ie.

Types of Meiosis Errors

Trisomy and Monosomy

• Trisomy occurs when three copies of an chromosome is found in an offspring
• Monosomy may also occur when there is only a single copy of a chromosome
• These individuals are usually sterile as their sexual gamete production is not normal
  • It is more likely for children who have older parents at the time of sexual reproduction to inherit these errors

Condition Chart

• ie.

Down Syndrome (trisomy 21)

• Intellectual Challenges
• Shorter Stature
• Almond Shaped eyes
• Flattened Facial Features
• Abnormal palm creasing patterns

Edward Syndrome (trisomy 18)

• Intellectual and Physical Challenges
• Prominent Facial Features
• Extreme Muscle tone
• Shortened life span

Patau Syndrome (trisomy 13)

• Intellectual and physical challenges
• Variety of organ defects
• Large triangular nose
• Shortened Life Span

Klinefelter Syndrome (XXY)

• Sexual Immaturity
• Brest Swelling

Jacobs Syndrome (XYY)

• No unusual syndromes
• Some individuals may be taller than average

Triple X Syndrome (XXX)

• Do not exhibit or only exhibit mild symptoms
• Tall and thin
• Wide-set eyes
• Menstrual Irregularity

Turner Syndrome (XO)

• Only one X-chromosome
• Short Stature
• Webbed neck
• Sexually Underdeveloped
  • Also Monosomic, so likely sterile

Changes in Chromosomes

• 4 types
  • Deletion
    • Genetic Material is lost during crossing over
    • ie.
  • Duplication
    • Genetic Material is repeated
    • ie.
  • Inversion
    • Genetic Material is flipped from its normal position.
    • ie.
  • Translocation
    • Genetic Material is exchanged between two different chromosomes
    • ie.

References

2.0x Genetics
2.3 Meiosis