What percent of a person's dna matches their mother's, father's, grandparent's, aunts & uncles, and great...

Question

grand parents? Do people actually have a large amount of the exact same genes as their parents, or do people have a lot of genes from other people in their family too?

Answer 1

There is a simple answer, backed by a complex answer.

50% of a person;s DNA comes from the mother, 50% from the father.  This means that your mother, your father, your daughter, your son each SHARE 50% of the same DNA as yourself.  Siblings also share 50%; however, IDENTICAL twins have essentially the SAME DNA.  [However, as DNA changes in EACH individual as we age, the older the twins, the less their DNA would match.]  Following this out, each grandparent or each grandchild would share 25% of your DNA.

Aunts, uncles, nieces and nephews, as with grandparents and grandchildren, each share 25% of your DNA.

Great-grandparents, great-grandchildren, great-nieces/nephews AND first cousins all share 12.5% of your DNA.

Great-great-grandparents/children and first cousins once removed each share 6.25% of your DNA.

Second cousins 3.125%; second cousin once-removed 1.563%; second cousins twice-removed, 0.781%.

If you go out to ancestors and descendants, each succeeding generation would have 1/2 the shared DNA as the previos generation.

SOURCE: "Trace Your Roots with DNA Using Genetic Tests to Explore Your Family Tree" by Megan Smolenyak Smolenyak and Ann Turner.

Radiation (including natural radiation, present everywhere) CHANGES everyone's DNA, which is the cause of Mutations, etc.  Then you get into dominant genes and recessive genes.  As you know, both parents came have black hair, all 4 grandparents can have black hair and a child can be born with red hair (happened to my brother), blond hair or even WHITE (platinum blond) hair.  The same with eyes; everyone can have brown eyes (parents, grandparents) and the child can be born with hazel, green, gray or blue eyes.

So, the short answer is those percentages; this last part is the complicated answer.  There is so much more; check out a good book on DNA or check websites, such as www.familytreedna.com.

Answer 2

It is according to what kind of DNA.

Y DNA is solely passed from father to son.

Mitochondrial DNA is passed from mother to both sons and daughters but only the daughters pass it on to their children.

Most of our DNA is Autosomal. We get it 50-50 from both parents.  It is the only DNA that relates a female to her father or a male to his paternal grandmother or maternal grandfather.   Your genes come from all your ancestors that have gone before you.

Some of your genes are recessive and even though they don't show up in your appearance etc, they might show up in your children's and grandchildren's.

Answer 3

We share more than 99% of our total DNA with our relatives. In fact we share 99% of our DNA with chimpanzees and benobos. It is within that one percent where we look for DNA markers that we use to compare DNA like in genetic genealogy or forensic identification.