Population Dynamics Humans and malaria. Science (2010), v.328:841.
-
Upload
annabel-carroll -
Category
Documents
-
view
214 -
download
0
Transcript of Population Dynamics Humans and malaria. Science (2010), v.328:841.
![Page 1: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/1.jpg)
Population Dynamics
Humans and malaria
![Page 2: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/2.jpg)
Science (2010), v.328:841
![Page 3: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/3.jpg)
Global Map of Malaria
“…a far more urgent task: reducing the horrific toll of malariain central Africa, where five countries account for 50% of allglobal deaths from the disease and elimination is not possible.”Science (2010), v.328:849
![Page 4: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/4.jpg)
Malaria
![Page 5: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/5.jpg)
Malaria life cycle
http://www.cdc.gov/malaria/about/index.html
http://www.who.int/topics/malaria/en/
![Page 6: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/6.jpg)
Malaria is large threat to human health in equatorial
regions of the Earth
But some human populations show resistance to the disease.
How??
![Page 7: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/7.jpg)
Natural Selection• Overproduction• Environmental
pressure/competition• Pre-existing individual
variation• Heritable traits• Happens over generations
(time)• Happens in populations (not
single individuals)• Offspring must be viable and
fertile
![Page 8: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/8.jpg)
Darwin’s Inescapable Conclusion
– Fact 1: Potential for overproduction
and competition for existence
– Fact 2: Individual variation
– The inescapable conclusion:
Unequal reproductive successUnequal reproductive success• Darwin called this process natural selection.
• The result of natural selection is evolution when a population has adapted to its environment.
Evidence for humans?
![Page 9: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/9.jpg)
Human Population GrowthThe History of Global Population
Growth
![Page 10: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/10.jpg)
Darwin’s Inescapable Conclusion
– Fact 1: Potential for overproduction and competition for existence
– Fact 2: Individual variation
– The inescapable conclusion: Unequal reproductive successUnequal reproductive success
• Darwin called this process natural selection.• The result of natural selection is evolution when a
population has adapted to its environment.
Evidence for humans?
![Page 11: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/11.jpg)
The Modern Synthesis: Darwinism Meets Genetics
– The modern synthesis is the fusion of genetics with evolutionary biology.
Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings
![Page 12: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/12.jpg)
Populations as the Units of Evolution
– A population• Is a group of individuals of the same species
living in the same place at the same time.• Is the smallest biological unit that can evolve.
![Page 13: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/13.jpg)
– Population genetics• Focuses on populations as the evolutionary
units.• Tracks the genetic makeup of populations over
time.
![Page 14: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/14.jpg)
Genetic Variation in Populations
– Individual variation abounds in populations.• Not all of this variation is heritable.• Only the genetic component of variation is
relevant to natural selection.
![Page 15: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/15.jpg)
Sources of Genetic Variation in sexually reproducing
organisms– Mutations
• Are changes in the DNA of an organism.
– Sexual recombination• Crossing over• Independent assortment of chromosomes• Random fertilization
![Page 16: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/16.jpg)
– Hemophilia• Is a blood-clotting disease.
![Page 17: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/17.jpg)
Intergenerational Mutation Rate
• By how many mutations does your genome differ from your parents genome?
• Roach et al (2010) found about 60 mutations, 30 from each parent, that occurred during the formation of egg and sperm (meiosis).
![Page 18: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/18.jpg)
![Page 19: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/19.jpg)
Sickle-cell allele:genotype, phenotype, and
resistance to malaria
from The Human Evolution Coloring Book, 2nd Ed.
Malaria infection causescells to sickle. Sickled cells, along with parasite, are killed.
![Page 20: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/20.jpg)
Sickle-cell Allele
![Page 21: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/21.jpg)
Biochemistry of sickle-cell disease
from Steinberg, M.H., (2006), Trends Pharm. Sci., 27(4):204-210.
![Page 22: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/22.jpg)
Sources of Genetic Variation in sexually reproducing
organisms– Mutations
• Are changes in the DNA of an organism.
– Sexual recombination• Crossing over• Independent assortment of chromosomes• Random fertilization
![Page 23: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/23.jpg)
– Sexual reproduction depends on• Production of gametes through Meiosis.• Fertilization.
Meiosis, The Basis of Sexual Reproduction
Copyright © 2007 Pearson Education, Inc. publishing as Pearson Benjamin Cummings
![Page 24: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/24.jpg)
Gametes and the Life Cycle of a Sexual Organism
– The life cycle of a multicellular organism is the sequence of stages leading from the adults of one generation to the adults of the next.
![Page 25: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/25.jpg)
Figure 8.14
– Humans are diploid organisms.
• Their cells contain two sets of chromosomes
• Their gametes are haploid, having only one set of chromosomes
![Page 26: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/26.jpg)
– Fertilization• Is the fusion
of sperm and egg.
• Creates a zygote, or fertilized egg.
– Sexual life cycles involve an alternation of diploid and haploid stages.
![Page 27: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/27.jpg)
Eukaryotic Chromosomes– Each eukaryotic
chromosome contains one very long DNA molecule,
• Typically bearing thousands of genes.
– The number of chromosomes in a eukaryotic cell
• Depends on the species.
![Page 28: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/28.jpg)
– Homologous chromosomes are matching pairs of chromosomes.
–Humans have•Two different sex chromosomes, X and Y.•A female has XX•A male has XY•Twenty-two pairs of matching chromosomes, called autosomes.
Homologous Chromosomes
![Page 29: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/29.jpg)
Meiosis is the process where the two sets of homologous chromosomes are separated into different cells - egg or sperm.
Start with one cell with 2 sets of homologous chromosomes
End with 4 cells with 1 set of homologous chromosomes
How does this happen?
![Page 30: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/30.jpg)
Meiosis is the process where the two sets of homologous chromosomes are separated into different cells - egg or sperm.
![Page 31: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/31.jpg)
The Process of Meiosis
– In meiosis,• Haploid daughter cells are produced in diploid organisms.• Two consecutive divisions occur, meiosis I and meiosis II,
preceded by interphase.• Crossing over occurs.
From movie folder play:MeiosisOverview.html TelophaseICytokin.htmlInterphase.html ProphaseII.htmlProphaseI.html MetaphaseII.htmlMetaphaseI.html AnaphaseII.htmlAnaphaseI.html TelophaseIICytokin.html
![Page 32: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/32.jpg)
Figure 8.16.1
![Page 33: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/33.jpg)
Figure 8.16.2
![Page 34: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/34.jpg)
Figure 8.16.3
![Page 35: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/35.jpg)
Review: Comparing Mitosis and Meiosis
– All the events unique to meiosis occur during meiosis I.
![Page 36: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/36.jpg)
Figure 8.17
![Page 37: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/37.jpg)
The Origins of Genetic Variation
– Offspring of sexual reproduction are genetically different from their parents and from one another.
– Independent assortment of chromosomes– Random fertilization– Crossing over– Random mutations
![Page 38: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/38.jpg)
Independent Assortment of Chromosomes
– In independent assortment, every chromosome pair orients independently of the others during meiosis.
![Page 39: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/39.jpg)
Random Fertilization
– The human egg cell is fertilized randomly by one sperm, leading to genetic variety in the zygote.
![Page 40: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/40.jpg)
Crossing Over
– In crossing over,• Homologous
chromosomes exchange genetic information.
• Genetic recombination occurs.
From the movie folder play: - CrossingOver.html
![Page 41: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/41.jpg)
– What happens when errors occur in meiosis?
When Meiosis Goes Awry
![Page 42: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/42.jpg)
How Accidents During Meiosis Can Alter Chromosome Number
– In nondisjunction,• The members of a chromosome pair fail to separate
during anaphase.• Gametes with an incorrect number of chromosomes
are produced.
Copyright © 2007 Pearson Education, Inc. publishing as Pearson Benjamin Cummings
![Page 43: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/43.jpg)
Figure 8.20
![Page 44: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/44.jpg)
– The result of nondisjunction
![Page 45: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/45.jpg)
Down Syndrome: An Extra Chromosome 21
– Down Syndrome• Is a condition where an individual has an extra
chromosome 21.• Is also called trisomy 21.
![Page 46: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/46.jpg)
– The incidence of Down Syndrome increases with the age of the mother.
![Page 47: Population Dynamics Humans and malaria. Science (2010), v.328:841.](https://reader036.fdocuments.us/reader036/viewer/2022062804/56649eb35503460f94bb9d51/html5/thumbnails/47.jpg)
Abnormal Numbers of Sex Chromosomes
– Nondisjunction• Also affects the sex chromosomes.