Human Variation and Disease Risk

Malaria and Sickle Cell Anemia

• Malaria can trigger sickle cell anemia and increase the risk of death.

Human Variation

• Human variation refers to genetic diversity among humans.
• Patterns are influenced by natural selection, mutations, genetic drift, and gene flow.

Population Markers

• Population markers are characteristics used to identify populations.
• Example: Y-chromosome markers, passed from father to son.

Clinal Variation

• Clinal variation is gradual trait changes across a population.
• Closer populations have more similar traits.
• "Clinal" describes the pattern itself.

Genotypic Variation

• Genotypic variation refers to differences in genotypes among individuals within a population.

Human Origins (Journey of Man)

• Cradle of humanity: Primarily East Africa.
• Nursery of humanity: Sites in Africa where early humans developed.

HLA Haplotypes and Disease Risk

• Certain HLA haplotypes increase the risk of autoimmune diseases.
• HLAs are located on chromosome 6 (major histocompatibility complex).

HLA Diversity Factors

• Population size, genetic drift, natural selection, migration, and disease all influence HLA diversity.

Hemoglobinopathies

• Hemoglobinopathies are disorders caused by abnormalities in hemoglobin structure or production.
• Examples include sickle cell disease.

Endogamy and HLA Patterns

• Endogamy is mating within a specific group.
• Endogamy restricts the gene pool, increasing the frequency of certain HLA alleles and haplotypes.

Taxonomy and Classification

• Taxonomy is organizing organisms based on shared characteristics.
• Taxonomic classification organizes them into a hierarchical structure, reflecting relationships.
• Homologies are similarities from a common ancestor.
• Analogies are similar functions and appearances but not common ancestors.
• Binomial nomenclature: a formal two-part naming system for species.

Human and Chimp Species

• Humans: Homo sapiens
• Chimps: Pan troglodytes

Scientists

• Linnaeus: Developed binomial nomenclature and taxonomy.
• Cecil Rhodes: Involved in African expansion.

Primate Characteristics

• Larger brains, social behavior, flexible limbs, and forward-facing eyes are key characteristics.
• Bipedalism: Walking on two legs.
• Quadrupedalism: Walking on four limbs.
• Brachiation: Swinging from branch to branch.
• Clavicle: Collarbone connecting the arm to the body.

Hominid Classification of Chimps

• Chimps are classified with hominids due to shared ancestry and similar traits.

Animal Kingdom Characteristics

• Multicellularity, mobility, reproduction, nervous, and muscular systems are characteristics of the Animalia kingdom.

Linnaean Classification Hierarchy

• Linnaean classification categorizes species into progressively broader groups.

Disease Association with Haplotypes

• Specific haplotypes are associated with certain diseases (autoimmune diseases, Hodgkin's disease, stomach cancer).

Pheromones and the Sweaty T-Shirt Test

• Pheromones are chemical signals between individuals of the same species.
• The sweaty T-shirt test investigates pheromones.

Human Karyotype and HLAs

• Human karyotype: Complete set of chromosomes in an individual.
• HLAs: Human leukocyte antigens, genes that distinguish between self and non-self.

Plasmodium Species

• Plasmodium falciparum: Deadliest malaria parasite, transmitted by mosquitos.
• Plasmodium vivax: Second most common malaria parasite, transmitted by mosquitos.

Malaria Resistance

• Certain genetic traits, including sickle cell traits, thalassemia, and G6PD deficiency, offer some malaria resistance without severe health impacts.

This quiz covers key concepts related to human variation, including the effects of malaria on sickle cell anemia, genotypic differences, and population markers. It also explores clinal variation and the origins of humanity, particularly focusing on the genetic diversity that influences health and disease risks in populations.