Understanding Basic Genetic Genealogy and My DNA Results - PowerPoint Presentation

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Understanding Basic Genetic Genealogy and My DNA Results

Olivia Fordiani

The content of this video, as well as the thoughts, views, and opinions expressed herein belong solely to the creator and do not necessarily reflect the views of FamilySearch International and RootsTech.

Will my siblings have different DNA and ethnicity results than I have?

Who should I test in my family?

What does

cM

on my cousin matches page stand for?

How can

cM

help me figure out relationships?

How is a chromosome browser helpful to me?

Should I contact all of my matches, even the ones that I share only a little bit of DNA with?

Have you ever wondered…

Basics of Inheritance

Humans have 22 pairs of autosomes and one pair of sex chromosomes (XX for female, XY for male).

The genes on each chromosome specify certain traits like hair color or blood type. Each person has two variations of each gene, called alleles. One of the mother’s two alleles and one of the father’s two alleles is passed to the child so the child ends up with two alleles as well.

https://en.wikipedia.org/wiki/Gene

https://www.ncbi.nlm.nih.gov/books/NBK541156/

Male

https://support.ancestry.com/s/article/Unexpected-Ethnicity-Results

Chromosome Recombination (Crossing Over)

One copy of chromosome from mom and one from dad

Chromosomes replicate to form sister chromatids

Maternal and paternal chromosomes separate into different daughter cells during Meiosis 1

Sister chromatids separate into different daughter cells during Meiosis 2

Recombination allows for

genetic variation and diversity

Why siblings don’t look the same

https://

www2.palomar.edu/anthro/biobasis/bio_3.htm

text=There%20are%208%2C324%2C608%20possible%20combinations,to%20thousands%20of%20different%20genes

#:~:.

https://www.genome.gov/genetics-glossary/Crossing-Over

Percentages

Inherited

by G

eneration

https://support.ancestry.com/s/article/Unexpected-Ethnicity-Results

https://isogg.org/wiki/Cousin_statistics

Should My Siblings Get Tested?

Centimorgans

(

cM

)

A

c

entimorgan is a unit of measurement used to measure genetic linkage or distance along a chromosome.The more

cMs

shared between two people, the more closely related they will be.

I share 74

cM

with my cousin, which means that’s the distance along a chromosome, or the amount of DNA we share. Our 74 shared

cM

are broken into segments on different parts of our chromosomes.

DNA Painter S

hared

Centimorgan

Project

https://dnapainter.com/tools/sharedcmv4

Autosomes are 22 of your 23 chromosomes that specify traits passed down

Chromosomes cross over and genes are recombined which allows for

genetic variation and

diversity

Because of recombination, siblings look different and have inherited DNA from distant ancestors you may not have inherited DNA from – test your siblings!

Test the oldest generation in your family

Centimorgans

show

how much shared DNA you have with a relative. You can use the amount of

cM

shared to figure out relationships using The Shared

Centimorgan

ProjectChromosome browsers allow you to visualize where you share DNA with your matchesIf two of your matches share DNA with you at the same place on your chromosome, you share a common ancestor – you are a triangulated match.

Be wary of matches at about 7

cM

or lower – they could be false matches!

Takeaways

Thank you for your time! Please feel free to reach out to me via LinkedIn, Facebook Messenger, or E-mail if you have further questions.

LinkedIn

: https://www.linkedin.com/in/olivia-fordiani/

Facebook

: https://www.facebook.com/olivia.fordiani

/

E-mail: livymay@gmail.com