M4

Question 1

Lineage Testing

Answer 1

X - DNA
Y - DNA
mtDNA

Question 2

Lineage Testing can sometimes help

Answer 2

focus on particular branches and lines to follow, by either INCLUDING or EXCLUDING matches

Question 3

Lineage Testing can sometimes help to indicate

Answer 3

ETHNICITY or BIOGEOGRAPHIC ancestry (Y & mtDNA)

Question 4

X & Y Inheritance
Females have

Answer 4

2 X Chromosomes
* The 2 X chromosomes can be RECOMBINED before passing them to a child

Question 5

X & Y Inheritance
Males have only

Answer 5

1 X Chromosome
* The X DNA fathers pass on to a daughter is an EXACT copy of their own

Question 6

X & Y Inheritance

Sons receive a recombined copy of their

Answer 6

mothers X DNA and an exact copy of their Fathers Y DNA

Question 7

X-inactivation

Answer 7

At a certain point in the embryonic development of every female mammal one of the 2 X chromosomes in each cell INACTIVATES by supercoiling into a structure known as a BARR BODY.

Question 8

X-inactivation
Lyonization

Answer 8

An irreversible process that leaves only 1 active X chromosome in each cell of the female embryo. Only the alleles on the active (uncoiled) X chromosome are expressed.

Question 9

X-inactivation
If X-inactivation DID NOT happen, XX people would have

Answer 9

too much proteins made compared to XY people, therefore most of 1 of the X’s in XX people (random process/choice of which one) is shut down

Question 10

X-DNA analysis is Genetic Genealogy is

Answer 10

mostly useful for MALES
* Because their XDNA almost always has come from only from their biological MOTHER (they inherit their Y from their father)

Question 11

X-DNA in Genetic Genealogy

Consumer DNA testing companies DO analyze XDNA, however ONLY 2 report XDNA results

Answer 11

FTDNA and 23andMe

Question 12

X-DNA in Genetic Genealogy

XDNA is inherited from a

Answer 12

small subset of ancestors
** the pool of ancestors whom you share an XDNA cousin match w/is much smaller compared to atDNA cousin matches

Question 13

SNP Density

X Chromosome is relatively large (~150 million bp), however the number of SNPs tested by consumer DNA companies on the X Chromosome is

Answer 13

relatively SMALL compared to the other chromosome

Question 14

SNP Density

There’s lower SNP density observed. A shared segment

Answer 14

relatively FEW tested SNPs giving a GREATER CHANCE that is NOT a true shared segement

Question 15

SNP Density

In FIGG/GG we should FOCUS on

Answer 15

LARGER segments of shared XDNA, combined with atDNA shared segments.

Question 16

Caution with XDNA

Small segments of shared XDNA could be

Answer 16

false positives because of LOW SNP density
* You could waste time looking for a shared XDNA ancestor who doesn’t exist!

Question 17

Caution with XDNA
If you/your test kit DO NOT share XDNA with a match, it DOESN’t prove or DISPROVE any relationship. EXCEPT

Answer 17

1. A biological mother and her biological children (sons & daughters)
2. A biological father and his biological daughters
3. Biological sisters who have the same biological father

Question 18

Caution with XDNA

Half Siblings who DON’t share a biological father

Answer 18

may NOT share any XDNA

Question 19

Caution with XDNA

Full Sibling may NOT share

Answer 19

any XDNA as they may have inherited a DIFFERENT copy of the X chromosome from their MOTHER

Question 20

Y Chromosome

Answer 20

Only found in Males
Sons inherit from FATHERS
Inherited ALMOST unchanged through the PATERNAL line

Question 21

Y Chromosome

Psuedoautosomal regions may sometimes recombine,

Answer 21

those regions are NOT analyzed
in genetic genealogy or haplogroup determination

Question 22

Y Chromosome

Daughter OUT

Answer 22

• A Male ancestor does not have male descendants to carry his Y DNA forward

Question 23

Y Chromosome

There is NO limit on how many

Answer 23

generations back you can go to finding living YDNA relatives

Question 23

Y Chromosome

Daughter Out

YDNA should still be present in a male ancestors (who has daughter out)

Answer 23

brother’s children and grandchildren

Question 24

Y Chromosome

ALWAYs consider the possibility of

Answer 24

MISATTRIBUTED parentage
i.e., someone’s father may not actually be their biological father

Question 25

Y Chromosome

YDNA Tests

Answer 25

• Y STR Tests
• Y SNP Tests

Question 26

Y STRs

Y STRs are measured by the number

Answer 26

of repeats of a particular DNA sequence at a particular location, on the Y Chromosome

Question 27

Y STRs

Y STRs typically are named beginning with

Answer 27

DYS followed by some numbers
*number = related to the location on the Y chromosome

Question 28

Y STRs
DYS

Answer 28

DNAY Y-chromosome Segments

Question 29

YSTRs
Haplotype

Answer 29

the collection of specific marker results that characterize the tester.

YSTR tests have a wide range of the number of markers used. 37-700 markers

Question 30

YSTRs

Father and son will ALMOST always

Answer 30

have the exact same Y Haplotype

Question 31

Y STRs

Occasionally, a mutation may occur in a Y-STR marker

Answer 31

between generations
* E.g., 9 repeats become 10 in the next generation due to random error

Question 32

Y STRs

Some Y-STR markers may change/mutate more

Answer 32

frequently than others

i.e., have higher or lower mutation rates, yet these rates are relatively constant

Question 33

Y STRs

The number of differences between certain Y-STR markers of 2 people can be used to

Answer 33

estimate the time since those 2 people shared a common male ancestor

Question 34

Y STRs

1 mutation =

Answer 34

a More Recent Common Ancestor

Question 35

Y STRs

10 mutations (or more the mutations) =

Answer 35

a More Distant Common Ancestor

Question 36

Haplogroups

Answer 36

can provide (a hint) information about the ancient origins of a patrilineal line

Question 37

Haplogroups

Y-STRs can only

Answer 37

estimate haplogroups

Question 38

Haplogroups

Y-SNPs can

Answer 38

define haplogroups

Question 39

Y SNPs results can be

Answer 39

Ancestral = the person DOES NOT have a MUTATION at the SNP
or
Derived = the person has a MUTATION at that SNP

Question 39

Y DNA & Surname searches
YSTRs can be combined

Answer 39

with database searching for Surnames

Question 40

MRCA

Answer 40

Most Recent Common Ancestor