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OutlineY chromosome and history

advantages of using the Y chromosomeThomas Jefferson/Sally Hemings debate

genetic evidenceMitochondrial DNA

mitochondriainheritanceevolution

recent historyhuman evolution

Beverly1798

Harriet1795

Harriet1801

Unnamed1799

Madison1805

Sally Hemings

Eston Jefferson1808

Thomas Woodson?1790

Sally Hemingsʼ children

?

For Jefferson and Hemings history, check outhttp://www.monticello.org/plantation/hemingscontro/hemings-jefferson_contro.html

The StorySally Hemings, a slave of President Thomas Jefferson, had six or sevenchildren. In 1802 James Callender, a scandalmonger, published an articleaccusing President Jefferson of fathering the Hemingsʼ children.Arguments for: Children looked like Jefferson; Jefferson and Hemingswere in France or at Monticello together nine months before the birth ofeach of the children; Jefferson freed Sallyʼs children and other members ofher family. Madison claimed that Sally told him that Jefferson was hisfather and the father of his five siblings.Arguments against: Jeffersonʼs denial; Jeffersonʼs personality; difference inage; Madison and Eston were born after scandal; former Monticellomanager claimed another man was often seen leaving Sallyʼs quarters.There are two oral histories:The Jefferson/Randolph oral history: Peter and Samuel Carr fatheredSallyʼs children.

The Hemings oral history: Thomas Jefferson fathered Sallyʼs children.

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ConclusionsThomas Woodson was not the son ofThomas Jefferson or Peter or Samuel

Carr.

Eston Jefferson was not the sone ofeither Peter or Samuel Carr.

Eston Jefferson could have been the sonof Thomas Jefferson.

Shortly after the DNA test results were released inNovember 1998, the Thomas Jefferson Foundationformed a research committee consisting of ninemembers of the foundation staff, including four withPh.D.s. In January 2000, the committee reported itsfinding that the weight of all known evidence - from theDNA study, original documents, written and oralhistorical accounts, and statistical data - indicated a highprobability that Thomas Jefferson was the father ofEston Hemings, and that he was perhaps the father ofall six of Sally Hemings' children listed in Monticellorecords - Harriet (born 1795; died in infancy); Beverly(born 1798); an unnamed daughter (born 1799; died ininfancy); Harriet (born 1801); Madison (born 1805); andEston (born 1808).

Although the relationship between Jefferson andSally Hemings has been for many years, and willsurely continue to be, a subject of intense interest tohistorians and the public, the evidence is notdefinitive, and the complete story may never beknown. The Foundation encourages its visitors andpatrons, based on what evidence does exist, tomake up their own minds as to the true nature of therelationship.

The Thomas Jefferson Foundation

The Scholarʼs Commission, appointed by theThomas Jefferson Heritage Society, concluded thatthe allegation that Thomas Jefferson fathered SallyHemings is not proven. With the exception of onedissenter, the opinions range from skepticism to thecharge being false.

“One post-DNA commentator, historian JohndʼEntremont, perceptively noted that the “it-could-never-be-Thomas Jefferson” school is akin to areligion. As evidence is not required to sustain thefaith, there is little reason to believe that any amountof evidence could be offered to diminish it.”

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Thursday, March 1, 2007

Study Raises Possibility of Jewish Tiefor Jefferson

Article Tools Sponsored ByBy NICHOLAS WADEPublished: February 28, 2007

Was Thomas Jefferson the first Jewish president? Researchersstudying Jefferson’s Y chromosome have found it belongs to alineage that is rare in Europe but common in the Middle East,raising the possibility that the third president of the UnitedStates had a Jewish ancestor many generations ago.

16 million men or ~8% of a large part of Asian men have aY chromosome that is thought to have been inherited from

Ghengis Khan

OutlineY chromosome and history

advantages of using the Y chromosomeThomas Jefferson/Sally Hemings debate

genetic evidenceMitochondrial DNA

mitochondriainheritanceevolution

recent historyhuman evolution

Y chromosomes can beused to follow paternal

lineages

mtDNA can be used tofollow maternal lineages

Cells contain organelles

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Mitochondria are organelles that produce energy.

Mitochondria(red)

Nucleus

MitochondriaUse oxygen to produce energyefficiently (aerobic metabolism).-muscle cells are loaded withthem.Contain own small genome~17,000 bp circular DNA inhumansEncodes 2 rRNAs and 22 tRNAsfor protein synthesis13 proteins for energymetabolism99.9% of the mitochondrialproteins encoded by nucleargenes.

Electron micrographof a mitochondrion

Electron micrographof a mitochondrialDNA

Map of human mtDNA

Hypervariable region

Molecules that are not linked to chromosomesbearing nuclear centromeres behave differentlyduring mitosis and do not obey Mendel’s rules.

Organelle chromosomes

Mitochondria

Chloroplasts

Maternal Inheritance

mtDNA A

mtDNA B mtDNA D

mtDNA C

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Why?mitochondria

Oocytes contributecytoplasm, and hencemitochondria during

fertilization

Digression:How did mitochondria (and chloroplasts in plants) arise?

Lynn Margulis proposed the endosymbiont theory in the 1980s.She proposed that an anaerobic cell engulfed aerobic bacteria, andthe two cells developed a symbiotic relationship. With time most

bacterial genes ended up in the nucleus, but a few genes remained inwhat became mitochondria.

Evidence for Endosymbiont Theory

Similar lipid compositions in membranes of bacteria and mitochondria

Bacterial and mitochondrial genomes circular and lack associatedhistones

Protein synthesis in bacteria and mitochondria similar

rRNAs similar in bacteria and mitochondria