chloe
01-16-2010, 10:22 AM
Male Bonding: Y Chromosome (pp.35-38)
Note: Don't skip this because you are female.
The Source of All Y
Theoretically, the Y chromosome could be traced from every living man back to one man. Going back in time, the father of the father of the father, becomes a smaller and smaller number. It will all converge (coalescence) on one grandfather.
Y-Adam
The branches lead to the "Most Recent Common Ancestor" (MRCA). He is
nicknamed Y-Adam. He's not the first man, since he had to get his Y chromosome from his father. Y-Adam had his peers, was born in Africa, probably between 60,000 - 100,000 years ago and had at least 2 sons. They left African and migrated all over the world.
Practically Perfect
If the Y chromosome were duplicated perfectly, then every man in the world would have an identical Y chromosome. But it's tweaked a little bit sometimes when passed down. More and more sequencing of the Y chromosome allows scientists to pinpoint differences. Brothers might have a slight difference in their Y's and first cousins would have more of a difference. There is an optimal mutation rate that preserves Y for maybe 10-20 generations back. This is the Short Tandem Repeats (STRs). It's like a stutter. A short pattern (2-5 of the bases) is repeated a certain number of times: GATA could be GATAGATAGATAGATAGATA. Sometimes the enzyme that repeats loses its place and there will be only 4 repeats or 6 repeats. This copying "oops" happens 2/1000 (1/500 or 0.2%) on average.
What's the Catch?Mutations are random. The Y chromosome may be preserved for hundreds of
generations. Two brothers can have different markers, as no one know when the "oops" will happen. So, more than one test marker needs to be used: 10, 20, 30. Brothers would match on most markers. The law of averages says that two men could have a common ancestor within a certain time frame. The Y chromosome won't show WHO the ancestor is, only that you share a common ancestor at some point in time.
Define the PurposeThe report is a bunch of numbers. More and more people are testing and the DNA databases have more and more samples. Most people like the surname projects (Congrats to those who have already submitted their DNA to the Azores project, as surname projects won't work for us, since the Portuguese could take either surname).
Inset: Do You Really Want to Know?
How would you feel if the result wasn't what you were expecting?
Non-Paternity
The Y chromosome is not linked to the surname (adoption, infidelity,
illegitimacy (pai incognito for us Portuguese), aliases, and name changes would all cause this). 85% carry the surname down the lines.
Y - Chromosome ObjectivesOne doesn't have to do the straight paternal line. If you want to do a cousin line, then you will want a cousin who is associated with that surname. Most surname projects want to validate the written paper trail, prove a connection, or find a possible connection to somewhere else. More can be learned about the deep ancestry of an area by studying multiple surnames (like the Azores project).
Do You Have a Match?
Most people hope for a match, tracing their roots to a common ancestor. It can establish that you really are related. Of course, the opposite exists. If you are trying to eliminate a certain branch, then you hope for a mismatch. Testing answers questions or moves you closer to an answer.
Inset: What is a Match?
There are the names of the markers (such as: DYS390) with its results (such as 24, which is the number of repeats). Different companies put the markers in different orders, so if you are comparing FTNA with Relative Genetics, make sure you are matching up the markers as well. Haplotype is the complete set of results on whatever markers were tested.
Chart:
Abe: 14-12-24-11-13-13
Bob: 14-12-23-11-13-13
Carl: 14-12-24-11-13-13
Dan: 14-14-22-10-12-13
Abe and Carl are perfect matches and related; Bob may be closely related; Dan isn't related.
Very Common Common names use DNA to help narrow down their range. DNA could
differentiate branches. They can find distant cousins or rule out some branches (and thus save research time!)
Or Very Rare Having a rare surname may lead one to think that they are all related somewhere. DNA can prove that (or disprove it). This is where the DNA of the neighbors could help out (like in a geographical project like the Azores!)
Why Two Samples?
One test result has no one to compare to. So at least 2 people need to participate. More the distantly related the 2 people are, the deeper the chain of evidence. If the 2 people disagree on 1 marker then there was a mutation, but we don't know which person had the mutation. So a third person would have to submit their DNA. But the mutation will mark one branch of the descendancy chart. If the 2 people are quite different, then one has to rule out a non-paternity (that is, if they thought they were related in the first place).
Uncertain PaternityTales of adoption or illegitimacy fall in this category. If the family story says that all the Howrys, Hauris, Haurys, and Howreys were descended from the same ancestor, but great-grandpa was really a Hamilton, then DNA can show you whether to continue looking under the Howrey name or go look under Hamilton.
Geographic OriginsThis is more challenging than others. Similar names are needed, and a large sample of participants. Then you can tell which groups are related and which aren't (this was actually a long story on the Irish Glennons and how he went from county to county tracing those with similar names). In our case, some Portuguese have Miller instead of Mello, Marshall instead of Machado, or King instead of Rei. DNA testing would let those Millers know which Mellos they should go looking at in their research.
Name ChangesThe name may be confusing as it evolves over time (or changed upon entering another country). Y-DNA's fastest growing purpose is to substantiate the name change or uncover unknown ones.
Mystery MatchesIf your DNA matches someone out of the blue, then there could be a non-paternity, sound-alike names (Laymon & Lehman), Anglicized names, or patronymics. Also, the Most Recent Common Ancestor might be pretty far back.
When the Paper Trail is ConfusingWe deal with the name, date, and place. When there are 2 people who you think might be 1 person, then DNA can be used to determine this.
Why Y?Surname projects are the most common form of DNA testing. The Y chromosome goes straight down the paternal line. The mutation rate is just about right to trace. It can't prove descendancy from a certain ancestor, only that 2 people are related. DNA is another form of evidence to reinforce the traditional paper trail.
Chapter 4: Maternal Legacy: Mitochondrial DNA (pp. 59-74)
Mitochondrial DNA is in some ways parallel to the Y chromosome, except it tracks the straight maternal line.
A Different Kind of DNAThis DNA is in the cytoplasm of a cell. The mitochondria breaks down food molecules. If more energy is needed, the mitochondria splits in two.
Passing the Torch to the Next GenerationThe egg has as many as 100,000 mitochondria. They all come from the egg, which comes from the mother's egg, which comes from her mother's egg, etc. So it's the bottom line of the pedigree chart.
Mitochondrial EveTheoretically, everyone could trace his or her ancestry back to one woman, Mitochondrial Eve. She was born somewhere in Africa, about 120,000 - 200,000 years ago, long before Y-Adam. She wasn't the first or the only woman of the time period, but everyone goes back to her. The differences we see today in mitochondria are due to mutations.
References Supplied Upon RequestThe results are a long string of letters, between 340 - 1,100 bases. Everyone is compared with a single reference point and only the differences are reported. There is a very small number of these differences or polymorphisms. The total mitochondrial molecule is 16,569 bases long and fits on 3 pages. It is called the Anderson or the Cambridge Reference Sequence (CRS). The CRS is not the same as mitochondria Eve, or even close. It is one of the more common patterns in Europe.
Everyone's a Little Bit HyperThe mitochondria DNA makes a circular molecule. They started "base 1" at the center of the "D-loop." The D is for displacement or control region. Usually it is called the Hypervariable Region, or HVR. The D-loop is a spacer. Mutations cause no harm. Polymorphisms (differences) show up within the D-loops. The mutation rate is very low.
Test ReportsScientists sequence several hundred bases in the Hypervariable Region. Some companies list the actual sequence and some point out where you differ from the CRS. The report may list the mutations, but it is more correct to say "differences" or "polymorphisms." If you see 16224C 16311C, then that means you have base C at positions 16224 and 16311. (If you want to see the entire sequence, go to www.mitomap.org/mitomap/mitomapRCRS.txt). The complete set of polymorphisms is your haplotype. The mtDNA polymorphisms come as a package deal, not a mixture from different ancestors.
Compared with Whom?There is a common maternal ancestor back in time. It could be recent or thousands of years ago. It has been found in the Iceman. With mtDNA testing, the mitochondrial DNA changes more slowly than the Y-chromosome so the time frame broadens. It is harder to get a match with mtDNA. Comparisons between 2 specific people can show if there is a connection.
Proof of PrincipleThree objectives: For genealogists to study their maternal ancestry, for population geneticists to gain insight into the structure of early colonial populations, and for geneticists to determine the mutation rate of mtDNA.
Just a Coincidence?Scientists have found 460 unique haplotypes on positions 16024 and 16365. If more bases were included, the diversity would increase further.
Mailing List LaunchThere's one at: lists.rootsweb.com/index/other/DNA/GENEALOGY-DNA.html
http://www.dnaancestryproject.com/?gclid=CN-R6Z6aqZ8CFQ4MDQodEmEe1Q
Note: Don't skip this because you are female.
The Source of All Y
Theoretically, the Y chromosome could be traced from every living man back to one man. Going back in time, the father of the father of the father, becomes a smaller and smaller number. It will all converge (coalescence) on one grandfather.
Y-Adam
The branches lead to the "Most Recent Common Ancestor" (MRCA). He is
nicknamed Y-Adam. He's not the first man, since he had to get his Y chromosome from his father. Y-Adam had his peers, was born in Africa, probably between 60,000 - 100,000 years ago and had at least 2 sons. They left African and migrated all over the world.
Practically Perfect
If the Y chromosome were duplicated perfectly, then every man in the world would have an identical Y chromosome. But it's tweaked a little bit sometimes when passed down. More and more sequencing of the Y chromosome allows scientists to pinpoint differences. Brothers might have a slight difference in their Y's and first cousins would have more of a difference. There is an optimal mutation rate that preserves Y for maybe 10-20 generations back. This is the Short Tandem Repeats (STRs). It's like a stutter. A short pattern (2-5 of the bases) is repeated a certain number of times: GATA could be GATAGATAGATAGATAGATA. Sometimes the enzyme that repeats loses its place and there will be only 4 repeats or 6 repeats. This copying "oops" happens 2/1000 (1/500 or 0.2%) on average.
What's the Catch?Mutations are random. The Y chromosome may be preserved for hundreds of
generations. Two brothers can have different markers, as no one know when the "oops" will happen. So, more than one test marker needs to be used: 10, 20, 30. Brothers would match on most markers. The law of averages says that two men could have a common ancestor within a certain time frame. The Y chromosome won't show WHO the ancestor is, only that you share a common ancestor at some point in time.
Define the PurposeThe report is a bunch of numbers. More and more people are testing and the DNA databases have more and more samples. Most people like the surname projects (Congrats to those who have already submitted their DNA to the Azores project, as surname projects won't work for us, since the Portuguese could take either surname).
Inset: Do You Really Want to Know?
How would you feel if the result wasn't what you were expecting?
Non-Paternity
The Y chromosome is not linked to the surname (adoption, infidelity,
illegitimacy (pai incognito for us Portuguese), aliases, and name changes would all cause this). 85% carry the surname down the lines.
Y - Chromosome ObjectivesOne doesn't have to do the straight paternal line. If you want to do a cousin line, then you will want a cousin who is associated with that surname. Most surname projects want to validate the written paper trail, prove a connection, or find a possible connection to somewhere else. More can be learned about the deep ancestry of an area by studying multiple surnames (like the Azores project).
Do You Have a Match?
Most people hope for a match, tracing their roots to a common ancestor. It can establish that you really are related. Of course, the opposite exists. If you are trying to eliminate a certain branch, then you hope for a mismatch. Testing answers questions or moves you closer to an answer.
Inset: What is a Match?
There are the names of the markers (such as: DYS390) with its results (such as 24, which is the number of repeats). Different companies put the markers in different orders, so if you are comparing FTNA with Relative Genetics, make sure you are matching up the markers as well. Haplotype is the complete set of results on whatever markers were tested.
Chart:
Abe: 14-12-24-11-13-13
Bob: 14-12-23-11-13-13
Carl: 14-12-24-11-13-13
Dan: 14-14-22-10-12-13
Abe and Carl are perfect matches and related; Bob may be closely related; Dan isn't related.
Very Common Common names use DNA to help narrow down their range. DNA could
differentiate branches. They can find distant cousins or rule out some branches (and thus save research time!)
Or Very Rare Having a rare surname may lead one to think that they are all related somewhere. DNA can prove that (or disprove it). This is where the DNA of the neighbors could help out (like in a geographical project like the Azores!)
Why Two Samples?
One test result has no one to compare to. So at least 2 people need to participate. More the distantly related the 2 people are, the deeper the chain of evidence. If the 2 people disagree on 1 marker then there was a mutation, but we don't know which person had the mutation. So a third person would have to submit their DNA. But the mutation will mark one branch of the descendancy chart. If the 2 people are quite different, then one has to rule out a non-paternity (that is, if they thought they were related in the first place).
Uncertain PaternityTales of adoption or illegitimacy fall in this category. If the family story says that all the Howrys, Hauris, Haurys, and Howreys were descended from the same ancestor, but great-grandpa was really a Hamilton, then DNA can show you whether to continue looking under the Howrey name or go look under Hamilton.
Geographic OriginsThis is more challenging than others. Similar names are needed, and a large sample of participants. Then you can tell which groups are related and which aren't (this was actually a long story on the Irish Glennons and how he went from county to county tracing those with similar names). In our case, some Portuguese have Miller instead of Mello, Marshall instead of Machado, or King instead of Rei. DNA testing would let those Millers know which Mellos they should go looking at in their research.
Name ChangesThe name may be confusing as it evolves over time (or changed upon entering another country). Y-DNA's fastest growing purpose is to substantiate the name change or uncover unknown ones.
Mystery MatchesIf your DNA matches someone out of the blue, then there could be a non-paternity, sound-alike names (Laymon & Lehman), Anglicized names, or patronymics. Also, the Most Recent Common Ancestor might be pretty far back.
When the Paper Trail is ConfusingWe deal with the name, date, and place. When there are 2 people who you think might be 1 person, then DNA can be used to determine this.
Why Y?Surname projects are the most common form of DNA testing. The Y chromosome goes straight down the paternal line. The mutation rate is just about right to trace. It can't prove descendancy from a certain ancestor, only that 2 people are related. DNA is another form of evidence to reinforce the traditional paper trail.
Chapter 4: Maternal Legacy: Mitochondrial DNA (pp. 59-74)
Mitochondrial DNA is in some ways parallel to the Y chromosome, except it tracks the straight maternal line.
A Different Kind of DNAThis DNA is in the cytoplasm of a cell. The mitochondria breaks down food molecules. If more energy is needed, the mitochondria splits in two.
Passing the Torch to the Next GenerationThe egg has as many as 100,000 mitochondria. They all come from the egg, which comes from the mother's egg, which comes from her mother's egg, etc. So it's the bottom line of the pedigree chart.
Mitochondrial EveTheoretically, everyone could trace his or her ancestry back to one woman, Mitochondrial Eve. She was born somewhere in Africa, about 120,000 - 200,000 years ago, long before Y-Adam. She wasn't the first or the only woman of the time period, but everyone goes back to her. The differences we see today in mitochondria are due to mutations.
References Supplied Upon RequestThe results are a long string of letters, between 340 - 1,100 bases. Everyone is compared with a single reference point and only the differences are reported. There is a very small number of these differences or polymorphisms. The total mitochondrial molecule is 16,569 bases long and fits on 3 pages. It is called the Anderson or the Cambridge Reference Sequence (CRS). The CRS is not the same as mitochondria Eve, or even close. It is one of the more common patterns in Europe.
Everyone's a Little Bit HyperThe mitochondria DNA makes a circular molecule. They started "base 1" at the center of the "D-loop." The D is for displacement or control region. Usually it is called the Hypervariable Region, or HVR. The D-loop is a spacer. Mutations cause no harm. Polymorphisms (differences) show up within the D-loops. The mutation rate is very low.
Test ReportsScientists sequence several hundred bases in the Hypervariable Region. Some companies list the actual sequence and some point out where you differ from the CRS. The report may list the mutations, but it is more correct to say "differences" or "polymorphisms." If you see 16224C 16311C, then that means you have base C at positions 16224 and 16311. (If you want to see the entire sequence, go to www.mitomap.org/mitomap/mitomapRCRS.txt). The complete set of polymorphisms is your haplotype. The mtDNA polymorphisms come as a package deal, not a mixture from different ancestors.
Compared with Whom?There is a common maternal ancestor back in time. It could be recent or thousands of years ago. It has been found in the Iceman. With mtDNA testing, the mitochondrial DNA changes more slowly than the Y-chromosome so the time frame broadens. It is harder to get a match with mtDNA. Comparisons between 2 specific people can show if there is a connection.
Proof of PrincipleThree objectives: For genealogists to study their maternal ancestry, for population geneticists to gain insight into the structure of early colonial populations, and for geneticists to determine the mutation rate of mtDNA.
Just a Coincidence?Scientists have found 460 unique haplotypes on positions 16024 and 16365. If more bases were included, the diversity would increase further.
Mailing List LaunchThere's one at: lists.rootsweb.com/index/other/DNA/GENEALOGY-DNA.html
http://www.dnaancestryproject.com/?gclid=CN-R6Z6aqZ8CFQ4MDQodEmEe1Q