Kami Export - Human genetics NGSS 25

Chapter 15: Human Genetics

Page 1: Introduction

• Title: Human Genetics

• Chapter Number: 15

Page 2: Phenomenon Model #1

• Observations during the video:

  • (List actual observations)

• Questions about the video:

  1. (Question 1)

  2. (Question 2)

  3. (Question 3)

  4. (Question 4)

  5. (Question 5)

• Personal Experiences:

  • (List personal experiences related to the questions)

• Most Important Question:

  • (Identify the most critical question)

• Model Drawing:

  • Include how the disorder was acquired and its effects on the body.

Page 3: Sex Determination

• Who determines the sex of the baby?

  • Answer: Male

• Tragic History:

  • Reference to Henry VIII of England related to gender determination.

Page 4: Sex Determination

• Types of Chromosomes:

  1. Autosomes:

     • All chromosomes other than sex chromosomes (22 pairs).

  2. Sex Chromosomes:

     • Determine individual sex (1 pair; XX for female and XY for male).

Page 5: Chromosomes

• Homologous Chromosomes:

  • Body cells have paired chromosomes known as homologous chromosomes.

  • Karyotype:

    • Duplicated chromosomes composed of two sister chromatids.

    • Different lengths of sex chromosomes in males.

Page 6: Probability of Baby's Sex

• Siblings' Influence:

  • Probability of the next baby being a boy or girl: 50%.

  • Explanation: Mother always provides X chromosome, and father can provide either X or Y.

Page 7: Types of Inheritance

• Refresh Memory on Inheritance Types:

  1. Complete Dominance

  2. Incomplete Dominance

  3. Codominance

  4. Multiple Alleles

  5. Polygenic Traits

Page 8: Sex-linked Traits

• Definition:

  • Traits controlled by genes on sex chromosomes.

  • X-linked: genes carried on the X chromosome.

  • Y-linked: genes carried on the Y chromosome.

Page 9: Examples of Sex-linked Traits

• Disorders:

  1. Colorblindness: difficulty distinguishing red and green.

  2. Hemophilia: inability to clot blood due to lack of platelets.

Page 10: Inheritance of Sex-linked Traits

• Passing on these traits to males vs. females:

  • Females:

    • Genotypes: XHXH (normal), XHXh (carrier), XhXh (affected).

  • Males:

    • Genotypes: XHY (normal), XhY (affected).

Page 11: Inheritance of Hemophilia (Carrier Parents)

• Genotype of Parents:

  • Mother: Carrier (XhX)

  • Father: Normal (XY)

  • Resulting Offspring:

    • 50% sons without hemophilia, 50% daughters carriers of hemophilia.

Page 12: Inheritance of Hemophilia (Affected Father)

• Genotype of Parents:

  • Father with hemophilia (XhY)

  • Mother without hemophilia (XX)

  • Resulting Offspring: Daughters as carriers, sons without hemophilia.

Page 13: X-linked Practice Problem

• Question:

  • A colorblind man married a carrier.

  • Percentage of daughters who will be colorblind and sons being colorblind.

Page 14: Drosophila (Fruit Fly) Genetics

• Example of Genetic Traits in Fruit Fly:

  • Red-eyed male (X+Y) and white-eyed female (XwXw)

Page 15: Pedigree Charts

• Definition:

  • Flow chart showing genetic history across generations.

  • Useful for predicting genetic conditions in families.

Page 16: Reading a Pedigree

• Symbols in Pedigrees:

  • Horizontal line: marriage/mating

  • Vertical line: offspring connection

  • Square: male; Circle: female

  • Shading: affected by the trait, blank: unaffected.

Page 17: Pedigree Analysis

• Determinations:

  • Identify if traits are dominant, recessive, autosomal, or sex-linked for specific genetic conditions.

  • Example: Huntington's Disease, Hemophilia.

Page 18: Autosomal Trait Pedigree

• Recessive Traits:

  • Require both parents to pass on recessive alleles for the trait to appear in children.

  • Dominant traits show up in each generation.

Page 19: Sex-linked Trait Pedigree

• Characteristics:

  • More males affected compared to females; only females are carriers (heterozygous).

Page 20: Genetic Disorders from Mutations

• Examples:

  1. Sickle Cell Anemia:

     • Autosomal recessive.

     • Causes sickle-shaped red blood cells, leading to poor circulation and pain.

  2. PKU:

     • Autosomal recessive; leads to buildup of phenylalanine causing mental retardation, managed with diet.

Page 21: Tay Sach’s Disease

• Description:

  • Autosomal recessive; leads to loss of enzymes, resulting in blindness and death at a young age.

Page 22: Cystic Fibrosis

• Description:

  • Autosomal recessive; dysfunctional chloride ion channel leads to mucus build-up, causing respiratory and digestive issues.

Page 23: Huntington’s Disease

• Characteristics:

  • Autosomal dominant; neurological deterioration with late onset symptoms (30s-50s).

Page 24: Duchenne Muscular Dystrophy

• Description:

  • Sex-linked (recessive); loss of muscle mass due to dystrophin gene mutation.

Page 25: Genetic Advantages

• Cystic Fibrosis and Typhoid:

  • CF allele helps block typhoid bacterium.

• Sickle Cell and Malaria:

  • Heterozygous individuals are resistant to malaria.

Page 26: Genetic Conditions and Their Effects

• Various genetic disorders and their implications, including:

  • Duchenne muscular dystrophy, Fragile-X syndrome, Retinitis pigmentosa, etc.

Page 27: Muscular Dystrophy Overview

• Definition:

  • Group of diseases causing progressive muscle weakness and mass loss due to genetic mutations.

Page 28: Duchenne Muscular Dystrophy (DMD)

• Gene Role:

  • Dystrophin protein on X chromosome; necessary for muscle fiber stability/protection.

Page 29: Karyotype Analysis

• Function:

  • Detect genetic disorders via chromosome abnormalities.

  • Method of collection involves amniotic fluid sampling.

Page 30: Chromosome Abnormalities Detection

• Types of abnormalities:

  • Monosomy (Turner Syndrome) or Trisomy (Down Syndrome) due to nondisjunction.

Page 31: Nondisjunction and Chromosomal Disorders

• Explanation:

  • Failure of chromosomes to separate during meiosis leading to abnormal chromosome numbers.

Page 32: Chromosomal Disorders Examples

• Examples:

  • Turner Syndrome (XO) and Klinefelter Syndrome (XXY).

Page 33: Down Syndrome Incidence

• Statistics:

  • Correlation of maternal age with incidence of Down Syndrome at birth.

Page 34: True or False Questions

• 1. False: Women do not determine baby gender.

• 2. False: Not guaranteed if father is colorblind.

• 3. True: More common in males.

• 4. True: Older mothers have higher risks for chromosomal issues.

• 5. True: Pedigrees show family inheritance patterns.

Page 35: X Chromosome Inactivation

• Description:

  • One X chromosome inactivates in females, observed in traits such as Calico cat coloration.

Page 36: Human Genome

• Definition:

  • Complete set of genetic information housed in DNA.

• Human Genome Project:

  • International project aimed at mapping and sequencing all human genes.

Page 37: DNA Manipulation Techniques

• Restriction Enzymes:

  • Cut DNA and are derived from bacteria.

• Genomic Imprinting:

  • Epigenetic chemical marks affect gene expression, passed down generations.

Page 38: Phenomenon Model #2

• Answer Questions:

  • Address the five questions derived from the previous video.

• Model Drawing:

  • Illustrate specific disorder affecting children, its inheritance, and physiological impacts.