The mtDNA SNP Backbone Test Panel examines 20 SNP markers in the coding region of the mtDNA.  These 20 SNP markers are the defining markers for determining an individual’s mtDNA haplogroup when used together with the HVR1 and HVR2 results.  The chart below lists the 20 markers that are included in this panel, and the haplogroups that they define. 

The diagram below is a phylogenetic tree illustrating how all people living today share a common maternal ancestor, the “mitochondrial eve”.  The diagram also shows where each mtDNA SNP marker appears in the tree.  Click here to download a detailed copy of the mtDNA Haplogroup Map. 

How it works:

The family tree section allows you to build a dynamic family tree using a Web 2.0 platform. The Web 2.0 platform has many advantages:

• Easy to share family tree with other living family members.
• Allows family members to collaboratively build onto the same tree.
• Instant communication and updates between living family members in the tree.
• Instant updates when the tree has been edited or changed.

Building your tree:

To access the family tree section, click “my family tree” on left side of page. This will bring you to the Pedigree View by default, with your own node as the “root” of the tree. The family tree can be displayed interchangeably in 1 of 3 ways:

1. Pedigree View
2. Family View
3. List View

The family tree is presented in “pedigree view” by default. By default, the user’s own node is chosen as the default root of the tree. Change the viewing method by clicking the other viewing choices at the top of the page.

Understanding the Pedigree View:

By default, the Family Tree section will display the Pedigree View. The Pedigree View displays a single node as the root of the tree and displays a set number of generations of ancestors from the root node.

Root Node - The root node is the node on the far left side of the page. The pedigree view will always display a set number of generations of ancestors from the root node.

Default root node - When viewing your family tree from your own account, your own node will always be presented as the default root of your family tree, regardless of who created the tree.

Number of generations displayed - By default, 4 generations are displayed at a time in the pedigree view. Using the generation selector at the top of the page, the user and choose to display from 2 to 6 generations at a time.

1. From the tree - Click on the “pedigree” link of any node in the tree to set that node as the root.
2. From the list - A list of all individuals in your family tree is listed in the left side of the page. Click on the “pedigree” link of anyone in the list to set that individual as the root of the tree.

Building the tree - Build the family tree by adding new nodes to the family tree. If a node is missing in the tree, it will indicate [Not Found], followed by the option to Add Father/Add Mother. Click on the add link to add an individual to that spot in the family tree. You can add parents, grandparents, and great-grandparents to the tree from the pedigree view by clicking “add mother” or “add father” link.

Editing existing nodes in the tree - To edit an existing node, click on the “family view” link for the node to be edited. All necessary edits can be accomplished from the family view (see below).

Understanding the Family View:

The family view displays one single family unit at a time. A family unit consists of one father, one mother, and all of their children. The Family View is the best place to build and edit the family tree.

Husband / Wife - By default, the root node will be displayed as either the Husband or the Wife of the family unit.

Add a spouse - If a spouse is missing, the family view will display the fields required to add the missing spouse to the family unit.

Adding additional spouses - If an individual has more than one spouse, additional spouses can be added by clicking “show all” link next to “spouses”, then click “add spouse” to add additional spouses.

Adding children - If there are no children in the family unit, the family view will automatically display the fields required to add a child. Once a child has been added, additional children can be added by clicking “add child” link in the Family View.

Linking existing nodes - If an individual exists in more than one place in the family tree, a single node can be linked to more than one place in the family tree using the “link existing node” link. Whenever a spouse or child is added to a family unit, you have the option to create a new node or to link an existing node in that position. To link an existing node, click “link existing node”, then enter the username or ID# of the node to be linked to that position of the family tree.

Adding parents - To add parents to the husband or wife of a family unit, click the “view parents” link of the husband or the wife. This will show the family view where the husband or wife are the children and their parents are the spouses. The parents can be added or edited in this view.

Correcting mistakes in the family tree - A mistake can be corrected by editing incorrect information in an existing node or by deleting the node from the tree.

How to edit a node - The information of a node can be edited by clicking the “edit” link for that node in the family view.

How to delete a node - If a node has been placed in the wrong place in the tree or is incorrect and needs to be removed, click “unlink node” in the family view. This will allow you to instantly remove the incorrect node. Please note that this will also remove the entire branch that is connected to the node. Once a node has been unlinked from your tree, it (and all nodes connected to it) can be found in the “unlinked nodes” list. To access the unlinked nodes list, click the appropriate icon at the top of the page. This list will contain all nodes which you have created which are no longer linked to your tree. You can choose to delete the nodes or to re-link them to the correct place in your tree.

How to add an existing node - To add an existing node or to merge another tree into your tree, click the “link existing node” feature to add an existing node to the correct place in your tree. Once the node has been added, all nodes which are linked to the node that you have added will also be brought into your family tree.

Understanding the List View:

The List View displays all of the nodes in your family tree in a list format. The list can be sorted (by name, by ID, by gender, by status), by clicking on the appropriate column at the top of the page.

The mtDNA SNP Haplogroup H Subclade Test Panel examines 17 unique SNP markers in the coding region of the mtDNA.  These 17 SNP markers define up to 16 different subclades of Haplogroup H (Subclades 1 to 16).  The chart below lists the 17 SNP markers that are included in this panel and the Subclades that they define.

The diagram below is a phylogenetic tree illustrating the various subclades of H that are known.  The diagram also shows where each of the 17 SNP fall in the tree.  Click here to download a detailed copy of the Haplogroup H Subclade Map. 

Like the HVR1 region, the HVR2 region of the mtDNA contains an abundance of SNP markers and is a rich source of ancestral markers for individuals wishing to trace their maternal ancestry.  Not only does it supplement the results of the HVR1 test when used in comparison studies, the HVR2 regions also contains important markers for definining an individual’s haplogroup. 

The phylogenetic tree below illustrates where some of the critical SNP markers are located.  Click here to download a detailed copy of the mtDNA Haplogroup Map. 

Region:   1 - 400

The mtDNA HVR1 region spans positions 16,000 to 16,500 of the mtDNA and contains an abundance of SNP markers which provide extremely useful information for determining an individual’s maternal ancestry.  The mtDNA HVR1 region is tested using a method known as “sequencing” to read the genetic code of the entire HVR1 region. 

Once your mtDNA HVR1 sequence is known, it is compared to a reference sequence known as the “Cambridge Reference Sequence” (CRS).  Click here to read more about the CRS.  Any region of your sequence that differs from the CRS is considered a SNP mutation.  Your mutations are presented to you in a mutation table after your test is completed.  Your set of mtDNA SNP markers is unique to you and your maternal line and contains valuable information about your maternal ancestors.  Your mtDNA results allow you to trace your deep maternal ancestry:

1.  Tracing maternal ancestry by direct comparison - compare your mtDNA profile to others

• Compare with family and friends
• Compare to other Genebase Users
• Compare to different ethnic groups

2.  Tracing deep maternal ancestry - determine your mtDNA haplogroup

Markers in the HVR1 region which are useful for Haplogroup determination are indicated in “blue” in the phylogenetic tree below.  Click here to download a detailed copy of the mtDNA Haplogroup Map. 

Region:   16001 - 16520

The Y-DNA SNP Haplogroup Backbone Panel contains 19 SNP markers throughout the Y-DNA.  These 19 SNP markers are the defining markers for an individual’s Y-DNA haplogroup.  The chart below lists the 19 markers that are included in this panel, and the haplogroups that they define.

The diagram below is a phylogenetic tree illustrating how all people living today share a common paternal ancestor, the “Y-Chromosomal Adam”.  The diagram also shows where each Y-DNA SNP marker appears in the tree.  Click here to download and print a detailed copy of the Y-DNA Haplogroup Map. 

What are the steps involved in participation?

1. Participants must have DNA markers obtained through DNA testing. Begin by obtaining a participation kit. Existing Genebase users should log into their control panel, click “DNA Ancestry Project”, then follow the instructions in the control panel to obtain a kit. Kits can also be ordered for friends and family members by clicking on “my markers” and then clicking “order test”.
2. The participation kit contains supplies for collecting a DNA sample from inside the mouth. The DNA sample is collected by rubbing two brushes inside the mouth against the cheek for 15 seconds. The proceedure is painless. After the sample is collected, the brushes are placed into specimen envelopes and sent to the laboratory for analysis.
3. Depending on the type of analysis, the turnaround time can range from 3 to 12 weeks. Once results are available, they are uploaded directly to the database and can be accessed through the user’s control panel. The user has control over the privacy settings of the markers. When the markers are set to “public”, the user can use them to search the database to look for matches and take part in DNA projects.

What is it?

The DNA Ancestry Project Database contains a dynmic collection of genetic genealogy information. The database can be divided into four types.

Y-DNA STR Database

The Y-DNA STR Database was the first database type available on Genebase. The STR database stores the allele values of over 75 genetic loci. This database is ideal for surname research and tracing ancestry on the paternal line. It is also useful for individuals searching for exact or close matches to other males who are descendents of the same paternal line.

Y-DNA SNP Database

The Y-DNA SNP database stores SNP markers and is intended for users who are interested in researching their deep ancestry and determining their haplogroup. The haplogroup can be predicted with the STR test, but the only way to confirm a haplogroup prediction is with SNP analysis.

mtDNA Mutation / SNP Database

The mtDNA mutation/SNP database records the markers in the mtDNA (a mutation/marker represents a region of the mtDNA which is different from the Cambridge Reference Sequence, CRS).

mtDNA Sequence Database

The entire length of the DNA tested is stored and can be downloaded and compared to other sequences.

What is the DNA Ancestry Project?

The DNA Ancestry Project is a online database built on a Web 2.0 platform which connects genealogists from around the world and facilitates genetic genealogy research through user to user connections and user to laboratory data source connections.

Once participants obtain their ancestral markers through Genebase, participation in many of the search and analysis features of the project is free. The Project aims to connect people with new developments in Genetic Genealogy by providing a direct link from users to scientific studies. As new studies and data become available, the data is available for searching and comparison by project members. Finding a match in the scientific databases can help users to make new discoveries and family connections across many generations.

The database contains “deep ancestry” data and studies (for tracing lineage back tens of thousands of years) as well as “family genealogy” data (for recent family studies tracing lines over the past few hundred years).

The database contains user data from around the world and continues to grow as membership grows. The family tree feature automatically links various lineages together to facilitate collaborative genetic genealogy studies between different family members to uncover the roots of different lines of the family tree. The database accepts user data which allows comparisons between active users in the project, as well as data from scientific studies which allows users to compare their data to real scientific studies.

The project contains the following database types:

• Y-DNA STR database - For tracing surnames and ancestry on the paternal line.
• Y-DNA SNP database - For tracing deep ancestry on the paternal line.
• mtDNA mutation/SNP database - For tracing ancestry on the maternal line.
• mtDNA sequence - For full mtDNA analysis and comparisons.

User-to-User Comparisons

The database facilitates the comparison of data between active users in the system to allow users to link up to other users and the system to look for matches, discover connections and look for geographical or ethnic correlations.

User to Scientific Studies Analysis

This feature allows users to connect their data to findings from the latest scientific studies and research data. As new findings emerge from various fields of study, the database will facilitate the interaction of users with the findings of the study so that users can see how the studies can shed light on their own data.

Who can join?

Anyone who has had their ancestral markers tested at Genebase will automatically become part of the DNA Ancestry Project.

History of the DNA Ancestry Project

1998 - Traditional DNA testing methods
Genetrack Biolabs processed Y-DNA and mtDNA testing and released results documents directly to clients.

October 2005 - Genebase Database Launched
Clients required a method to compare their DNA results with other clients. The first version of Genebase was launched in 2005 based on a Web 2.0 platform to allow DNA testing recipients to interact with each other and to compare DNA data. This version of Genebase only allows Y-DNA STR data and does not store Y-DNA SNP or mtDNA data.

August 2006 - Genebase 2.0 version developed
The second version of Genebase was developed to accomodate Y-DNA SNPs, and mtDNA data. The official launch of version 2.0 was held back pending completion of the GEDCOM feature.

May 2007 - Genebase 2.0 version launched
The newest version of Genebase is GEDCOM compatible and the database accomodates Y-DNA and mtDNA data, SNPs and full sequences.

MRCA stands for “Most Recent Common Ancestor”.  When comparing two individuals, the MRCA is the most recent ancestor from which the two individuals descended.   

TMRCA stands for “Time to Most Recent Common Ancestor”.  It’s a measure of how long ago two individuals likely shared a common ancestor.

Determining TMRCA through DNA testing:  On the paternal line, the TMRCA for two individuals can be predicted by testing markers on the Y-DNA called STR markers.  The more STR markers that are tested and compared, the more the test can narrow down the TMRCA value.

Example:

12 marker test:  If you and someone else test 12 STR markers, and matched each other perfectly at all 12 markers, your TMRCA is approximately 14.4. This means that you and the other individual likely shared a common ancestor between 0 to 14.4 generations ago. Now that’s a very broad time frame and does not provide solid evidence that two individuals are from the same line.

20 marker test:  If you and someone test more markers, such as 20 STR markers, and matched each other perfectly at all 20 markers, your TMRCA is narrowed down to 8.3. This means that you and the other individual likely descended from the same line and that you shared a common ancestor anytime between 0 to 8.3 generations ago.

44 marker test:  If you test 44 markers and match perfectly at all 44, your MRCA becomes only 3.8. This means that you and the other person shared a common ancestor between 0 and 3.8 generations ago.

As you can see, the more STR markers that are compared, the more informative the results.

Some haploytpes can be seen more frequently in certain parts of the world. For example, people whose ancestors are from the western coast of Europe often share in common a small group of Y-Chromosome STR markers. The group of Y-Chromosome markers which are frequently found in western Europe is called the Atlantic Modal Haploytpe (AMH). The AMH is characterized by the following markers:

DYS19 = 14
DYS388 = 12
DYS390 = 24
DYS391 = 11
DYS392 = 13
DYS393 = 13

More information about AMH can be found in Wilson et. Al. Genetic Evidence for Different Male and Female Roles During Cultural Transition in the British Isles. PNAD April 24, 2001 vol. 98, no. 9 pgs. 5078-5083.  Click here to download and print a copy of the original article. 

The AMH is tied to the R1b haplogroup.

Your Y-DNA haplotype is the specific set of results obtained after testing a set of STR markers on your Y-DNA. For example, if you take the 44 marker Y-Chromosome test, the combined result of all 44 markers is your unique haplotype and represents the unique genetic code for your paternal ancestral line.

Using your Y-DNA haplotype to search for or verify family linkages:  Your haplotype is the same or very close to that of all males who have descended from the same forefather as yourself.  That means that your father, grandfather and great-grandfathers along your paternal lineage all carry the same Y-DNA haplotype as you.  Also, all males living anywhere in the world today who descended from the same forefather as you will have the same or very similar Y-DNA haplotype as you.  Once you have tested your Y-DNA STR markers, you can use your haplotype to search for people who are linked to you on your paternal line.  You can also use it to verify whether any two individuals are descendents from the same paternal line.  Another common application is Surname Projects, which uses the Y-DNA haplogroup to determine how males with the same surname (last name) are connected to each other.

What is the difference between Y-DNA haplotype and Y-DNA haplogroup?

Y-DNA Haplotypes should not be confused with Y-DNA Haplogroups.  An individual’s Y-DNA Haplogroup represents his “deep ancestry”.  All males living today are descendents of a single individual who lived in Africa approximately 150,000 years ago.  Over time, our ancestors migrated out of Africa in waves and populated the world.  All males can be traced to one of less than two dozen main haplogroups (haplogroups are designated by letters, such as Haplogroup J).

Haplogroups are determined by testing a type of marker on the Y-DNA known as SNP (single nucleotide polymorphism) markers.  STR marker testing will not tell you your haplogroup, but in some instances, it can be used to predict your haplogroup as there are some correlations between certain haplotypes and haplogroups.  However, confirmation of haplogroups must be made through SNP testing. 

Haplogroups are useful for scientists who are studying human migration patterns and has archealogical value.

Genetic distance is defined as the total difference in allele values of different genetic markers between two individuals. The smaller the value of the genetic distance, the closer two individuals are related, and the more recently they shared a common ancestor (TMRCA). The method used to determine genetic distance for four different Y-DNA STR marker types is explained below.

A. Calculation of genetic distance for single-copy markers

For single-copy markers, the calculation is straightforward. The genetic distance for each single copy marker between two individuals is the absolute value of the difference between the value of the markers:

The total genetic distance between two individuals is the sum of the genetic distances of all markers compared.

B. Calculation of genetic distance for multi-copy markers Markers DYS385, DYS459, DYS464 and YCAII are multi-copy Y-STR markers.

For most multi-copy markers, genetic distance can be calculated by adding the differences in allele values for each of the two copies.

C. Calculation of genetic distance for multi-copy marker DYS464 - using Infinite allele model

Assuming mutations at different copies of the same marker took place in a single generation, the Infinite allele method counts the total difference between all copies of the same marker as 1, despite the fact that more than one mutation exists.

The genetic distance for DYS464 is calculated using this method.

D. Calculation of genetic distance for DYS389i/ii

DYS389i is embedded in DYS389ii; therefore, the DYS389i values are included in DYS389ii values. Genetic distance can be determined by adding up two differences: differences in DYS389i values and differences in the second part of DYS389ii values, which are obtained by subtracting the DYS389ii values by DYS389i values.

The Y-DNA contains several different STR Marker Types:

A. Single-Copy Markers

Single-copy markers are DNA markers that occur only once in the human genome, resulting in one allele value for the marker.

B. Multi-Copy Markers

Markers DYS385, DYS459, DYS464 and YCAII are multi-copy Y-DNA STR markers that typically have two copies.

Marker DYS464 can occur in 4 to 7 copies in the human genome and the method for calculating genetic distance for DYS464 differs from the method used for other multi-copy markers.

Multi-copy markers are genetic/DNA markers that occur more than once (ie more than one copy) in the human genome, resulting in different allele values for each copy. For example, the markers DYS385, DYS459 and YCAII are typically present at two different locations on the Y-chromosome; therefore, they are also termed “duplicated markers”. For each multi-copy marker, the same primer pair binds to different locations on the Y-chromosome, thereby amplifying more than one region simultaneously, resulting in more than one allele value for that marker. The allele values for each copy are not reported in any specific order, as the exact order of copies cannot be determined, but typically, the smaller allele value is reported first, followed by the larger allele value.

C. Special Multi-Copy Marker DYS389

DYS389 is a special marker. Unlike other multi-copy markers, only one location is amplified. The forward primer for DYS389 binds at a specific location on the Y-chromosome, whereas the reverse primer binds at two different locations. Such amplification yields two PCR products:  the shorter DYS389I fragment and the longer DYS389II fragment.

Y-DNA STR Testing Process:  Once your buccal swabs arrive in the testing laboratory, the following steps are involved to obtain your Y-DNA haplotype: 

1.  When the laboratory receives the cheek swab samples, the cells are removed from the swab into an eppendorf tube.

2.  The cells are then lysed (broken apart) to release the DNA.

3.  The DNA is purified and quantitated.

4.  The STR markers on the DNA are amplified using a process known as polymerase chain reaction (PCR). During PCR, the specific regions of the DNA to be analyzed are amplified so that they can be analyzed. A primer pair is used to amplify each marker.

5.  The DNA strand is heated to separate the strands and the primers anneal onto the DNA template. TAQ polymerase amplifies the region between the primers. The primers are designed to surround the STR marker.  Using a series of heating and cooling steps, the DNA is repeatedly amplified using this technique. In a matter of an hour, millions of copies of the Y-STR markers are produced from a single original DNA strand.  Each specific primer pair is labelled with a colored dye. Thus, all of the PCR products have a color coded label attached.

6.  The DNA fragments produced by the PCR reaction are examined using a laser (capillary laser sequencing). During sequencing, an electrical current is used to force the DNA fragments to pass through a gel matrix within a fine capillary tube into a laser beam. As the DNA passes across the laser beam, the laser beam records the type of dye associated with the fragment, and the size of the fragment is recorded (smaller fragments pass more quickly through the gel and larger fragments pass through more slowly).

7.  The results of the analyses appear as peaks on a computer output and these peaks each correspond to a Y-Chromosome marker. Based on the position of the peaks, the laboratory will be able to determine the exact number of repeats in the DNA marker and thus obtain the exact haplotype of that individual’s DNA.

A number of STR markers can be tested on the Y-DNA. The more markers that are tested, the more discriminating the matches when comparing to other individuals.

For example, comparison of 12 markers alone is generally not powerful enough to distinguish family lines and can give inconclusive results. The more markers that are available for comparison, the more discriminating the comparison becomes.

There are two major advantages for comparing more markers:

1.  To prevent false positives
2.  To obtain conclusive results

Scenario:

Mr. Jones has been studying his family’s ancestry for several years and has started a “Jones” family study based in Arizona. He is interested in confirming that his family line is linked to a “Jones” line in New York. Although there are rumours that the two lines are related, Mr. Jones does not have the paperwork to prove this link. Mr. Jones is also interested in finding out whether his line is linked to any other Jones lines worldwide.

Mr. Jones had previously chosen to test just 12 markers. After testing, he uses the 12 markers to search the DNA database and finds out that he is a perfect match to the Jones line in New York. However, he also finds that he has a perfect match to over 200 individuals in the database, and over half of them do not even share his surname. How is this possible? Does it mean that he is related to everyone who matches him at the 12 markers? No, this simply means that data from only 12 markers is not powerful enough to distinguish Mr. Jones from other family lines.

To clarify this, Mr. Jones decides to increase his markers to 20. He enters the results of his 20 markers into the database and this time narrows down the number of matches.  In fact, now, only 18 people match him perfectly at his 20 markers, including the Jones line in New York. Surprisingly, many of the individuals who used to match perfectly at 12 locations only match at 14 or less out of the 20 locations tested, confirming that there is no familial link with most of the 200 individuals identified in the 12 marker test (more than 3 mismatches indicates that two family lines are not closely related).

To further clarify the findings, Mr. Jones decides to upgrade to a 44 marker test. This time, he finds out that he is a perfect match at all 44 markers to only two lines, a Jones line in England, and a Jones line in the United States. After contacting the two lines and comparing paperwork and stories, Mr. Jones was able to confirm that his line was indeed definitely linked to both lines and he is now able to add both new lines to his family tree.

Surprisingly, Mr. Jones was also able to find out that only 43 out of the 44 markers matched with the Jones line in New York. This confirms that although the Jones line in New York is related to his line, they are likely more distantly related.

Mr. Jones also discovered that he had a close match to 4 other Jones lines (43 out of the 44 matched) and he is now pursuing the possibility that the 4 other lines are also distantly related to him (MRCA analysis dictates that 1 mutation occurs every 500 generations, and thus we would detect a mutation every 12 generations with the 44 marker test).

Mr. Jones is now trying to recruit more Jones males from throughout Europe to try to reconstruct and relink his family line.

Conclusion:

12 markers were not discriminating enough for Mr. Jones to pinpoint his family lines. After increasing to 20 markers, Mr. Jones was able to obtain more useful information and was able to eliminate false matches generated by the 12 markers. However, after increasing to 44 markers, Mr. Jones was able to pinpoint the people that he was looking for and was furthermore able to accurately answer his questions about his relationship to the Jones line in New York. Mr. Jones can continue to carry on his research, and as more and more people globally are tested and are added to the database, Mr. Jones will be able to reconstruct his family line in great detail and re-unite with Jones worldwide who are descendents of his family line.

STR Overview

A short tandem repeat (STR) is a type of DNA polymorphism where short sequences of DNA are repeated. STRs are usually considered “junk DNA” because they are introns and do not code for protein. The number of times a DNA sequence is repeated for a given STR is variable between different individuals and thus, STRs are often useful for forensic or genealogical studies.

Y-DNA STRs

The STRs found in the Y-DNA are very useful for genealogical studies to examine male lineage. A male individual’s Y-DNA STR is unique to his paternal line. That means that all males who are descendents from the same male lineage will have exactly the same or a very similar Y-DNA STR pattern.

Y-DNA Overview

The Y chromosome, also called the Y-DNA, is a sex determining chromosome which is found in males (it’s counterpart is the X chromosome).

Unlike all of the other chromosomes, the Y-Chromosome is unique because it is passed down relatively unchanged along the male lineage and thus holds valuable information about a male’s ancestry.

Uses in Genealogy

The Y-DNA carries information about an individual’s paternal ancestry. The following characteristics of Y-DNA make it suitable for paternal ancestry analysis:

1. It is found only in males and is inherited strictly from father to son (the same way that the surname is passed down).
2. It’s genetic code is very stable (low recombination rate).
3. It contains STR markers which can be used to trace an individual’s recent ancestry.
4. It contains SNP markers which can be used to trace an individual’s deep ancestry.
5. The Y-Chromosome is passed down directly from a father to all of his sons and remains relatively unchanged throughout the generations. For example, a distant male forefather will pass his Y-Chromosome down to all of his sons. His sons will then pass the same Y-Chromosome down to all of their sons in the next generation and so on. Thus, all males who are connected to a common forefather will have the same Y-Chromosome. This manner of inheritance is identical to the manner in which the surname is passed down in most cultures (i.e. from father to son along the male lineage). As a result, the Y-Chromosome will allow two males with the same or similar last name to determine whether they belong to the same original family line and will determine whether different family groups with the same surname are connected. The Y-Chromosome allows genealogists solve questions about their ancestry where no paperwork exists and can be used to discover and re-unite family lines.

Y-DNA testing

The Y-DNA test involves a panel of tests on the Y-Chromosome to uncover ancestral markers. The Y-DNA test can be performed on males only, since females do not carry the Y-Chromosome (the Y-DNA is passed down from a father to all of his sons). Females who wish to trace their paternal ancestry must test a male relative and use their markers (e.g. brother, father, male cousin on paternal line, nephew on paternal line, etc.) There are currently two types of Y-DNA tests:

Short Tandem Repeat (STR) testing - STR testing involes testing genetic markers on the Y-Chromosome (usually 20 or more markers) to determine the individual’s “haploytpe”. Each haplotype is unique to a male family line and is informative for individuals wishing to trace family lines, participate in surnaem project to trace the roots of their surname, and calculating how long ago two family lines shared a common ancestor. The haplotype also provides a prediction regarding the “haplogroup”, or deep ancestry from thousands of years ago.

Single Nucleotide Polymorphism (SNP) testing - Once a STR test is completed, SNP testing can be used to confirm the haplogroup prediction and even further refine thehaplogroup results.

Single nucleotide polymorphism (SNP) refers to a single nucleotide change in the DNA. For example, A to T, C to G, etc. The rate of SNP mutations is quite low compared to STR mutations, so SNPs are often used to trace “deep ancestry”, ancestry from thousands of years ago.

Mutations are changes in DNA which happen naturally and are the basis for evolution. A mutation occurs when DNA polymerase makes a mistake when copying the DNA strand during cell division, resulting in a slight change in the DNA of the newly created cell. When a cell divides (during a process called meiosis), the DNA in the original cell must make a copy of itself for the new cell. It does this through a process known as DNA replication. During DNA replication, an enzyme known as DNA polymerase makes a copy of the DNA using the original DNA strand as a template. Although this process is usually very accurate and results in an exact replica of the original DNA, on occasion, the DNA polymerase may miscopy a section of the DNA, resulting in a slight change in the newly formed DNA strand. This is called a mutation and although mutations do not occur frequently, they are an important part of evolution and occur naturally.

All people have 23 pairs of chromosomes, 46 in total. One chromosome from the pair is inherited from the mother and the other one is passed down from the father. The 23rd pair of chromosomes are the sex chromosomes. Females have two X Chromosomes, and males have one X Chromosome and one Y Chromosome (aka Y-DNA). The Y Chromosome in a male holds important information about that individual’s ancestry.