Lecture Slides THIRD EDITION Essentials of Physical Anthropology Clark Spencer Larsen
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Lecture Slides
THIRD EDITION
Essentials of Physical
Anthropology
Clark Spencer Larsen
Genetics: Reproducing Life and Producing
Variation
• Larsen. Essentials of Physical Anthropology
3
Genetics: Reproducing Life and Producing Variation
• Questions addressed in this chapter: – What is the genetic
code?
– What does the genetic code (DNA) do?
– How does understanding genes help us understand variation?
The Cell: Prokaryotes
• Prokaryotes
– 3.5 billion years old
– Single-celled bacteria
– No nucleus or organelles
M.I. Walker/Science Source
The Cell: Eukaryotes
• Eukaryotes
– 1.2 billion years ago.
– Some single-celled; all multicellular organisms (including humans)
– DNA contained in a nucleus
– Organelles
Eye of Science/ Science Source
The Cell: Somatic Cells and Gametes
• Somatic cells
– Body cells have full DNA (humans: 46 chromosomes)
– Mitosis
Michael Abbey/ Science Source Biophoto Associates/ Science Source
(c1): Michael Abbey/Science Source; (c2): SPL/ Science Source Jim Zuckerman/Media Bakery
The Cell: Somatic Cells and Gametes
• Gametes
– Eggs (ova) and sperm
– Half DNA (humans; 23 chromosomes)
– Meiosis
Eye of Science/ Science Source
Chromosomes
• DNA packaged in chromosomes
• Chromosome number varies by species
Biophoto Associ-ates/ Science Source; (camel): Richard Nowitz/National
Geographic Image Collection; (guinea pig): Corbis; (salamander):
Wolfgang Thieme/ dpa/ Corbis; (house fly): Nigel Cattlin/ Science
Source; (apple): Evans Caglage/ Dallas Morning News/ Corbis; (potato):
DK Limited/ Corbis; (petunia): Roy Morsch/ Corbis; (algae): JP Nacivet/
Getty Images; (lemur): Millard H. Sharp/ Science Source; (colubus
monkey): Mark boulton/ Science Source; (orangutan): Robert Garvey/
Corbis
DNA: The Blueprint of Life
• DNA Genes Chromosomes Genome
• Nuclear DNA: homoplasmic
DNA: The Blueprint of Life
• Mitochondrial DNA
DNA: The Blueprint of Life
• DNA structure
– Sugar
– Phosphate
– Nucleotide base • Adenine (A)
• Thymine (T)
• Guanine (G)
• Cytosine (C)
– A with T
– C with G
» CAAAT
» GTTTA
The DNA Molecule: Replicating the Code
Chromosome Types
• Homologous pairs
– Autosomes (22 pairs)
– Sex chromosomes (1 pair) • X and Y
• Male determines sex
• Karyotype
Steve Gschmeissner/ Science Source L. Willatt/ Science Source
Mitosis
Mitosis
Steve Gschmeissner/ Science Source
Meiosis
• Haploid: 23 chromosomes (no pairs)
• Recombination via crossing over – Haplotypes
• Translocations and nondisjunctions
Law of Independent Assortment
Law of Independent Assortment
DNA and Protein Synthesis
Clouds Hill Imaging Ltd./ Corbis
Visuals Unlimited/ Corbis
Transcription and Translation
• Transcription
– DNA transcribed into mRNA in the nucleus of the cell
• Translation
– mRNA translated into an amino acid chain at the ribosomes
Transcription
Translation
Regulatory Genes
• On/off switches for genes
– Marfan syndrome
– Chicken teeth
– Human hair
– Lactose intolerance or persistence
John Radcliffe Hospital/ Science Source
Bettmann/Corbis
Homeotic (Hox) Genes
Law of Segregation and Codominance
Polymorphisms: Variations in Specific Genes
• Exercises:
– Can mother with blood type A and father with blood type B have a baby with blood type O?
– Can a man with blood type AB be the father of a baby with blood type O?
Polygenic Traits and Pleiotropy
• Many traits polygenic – Height, skin color
• Many genes pleiotropic – Sickle-cell
• All traits a product of genes AND environment – Height and
nutrition
– Epigenetics
Lecture Slides
Essentials of Physical Anthropology
Clark Spencer Larsen
THIRD EDITION
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