Autosomal DNA

In Context 

  • A technique based on ‘Autosomal DNA’ has been used for the first time to identify the great-grandson and closest living relative of Sitting Bull.
    • Sitting Bull is a prominent 19th-century Native American leader.
    • He is most famous for his victory over US General George Armstrong Custer in the Battle of the Little Bighorn River in 1876.

About Autosomal DNA 

  • It is a term used in genetic genealogy to describe DNA that is inherited from the autosomal chromosomes. 
    • An autosome is any of the numbered chromosomes, as opposed to the sex chromosomes. 
  • A person inherits half of autosomal DNA from the father and a half from the mother which  means genetic matches can be checked irrespective of whether an ancestor is on the father or mother’s side of the family
  • The autosomal DNA technique can be used even when very limited genetic data are available.
    • If there is access to old DNA — typically extracted from bones, hair or teeth, they can be examined in the same way
  • Autosomal DNA tests can be used to confirm relationships with a high level of accuracy for parent/child relationships and all relationships up to the second cousin level. 
    • For all relationships additional contextual and genealogical information is required to confirm the nature of the relationship.
  •  Experts have expressed hope that it could be used in the future to identify living descendants of other long-dead historical figures.

Comparison of DNA and RNA

As both, DNA and RNA are used to store genetic information but there are clear differences between them. The following table summarizes the key points:

Comparison

DNA

RNA

Function

Long-term storage of genetic information; transmission of genetic information to make other cells and new organisms.

Used to transfer the genetic code from the nucleus to the ribosomes to make proteins. RNA is used to transmit genetic information in some organisms 

Structural Features

B-form double helix. DNA is a double-stranded molecule consisting of a long chain of nucleotides.

A-form helix. RNA usually is a single-strand helix consisting of shorter chains of nucleotides.

Composition of Bases and Sugars

deoxyribose sugar-phosphate backbone

adenine, guanine, cytosine, thymine bases

ribose sugar

phosphate backbone

adenine, guanine, cytosine, uracil bases

Propagation

DNA is self-replicating

RNA is synthesized from DNA on an as-needed basis.

Base Pairing

AT (adenine-thymine)

GC (guanine-cytosine)

AU (adenine-uracil)

GC (guanine-cytosine)

Ultraviolet Damage

DNA is susceptible to UV damage.

Compared with DNA, RNA is relatively resistant to UV damage.

Source: DTE