"THE RESULTS ARE IN - You are..... NOT the father!"

The world has seen many relationships end after the utterance of this sentence on the famous TV show, "Maury". As I was scrolling through Facebook the other day, I looked over at the "Now Trending" tab on the side and saw a link that said "DNA: Father Failed Paternity Test Due to ‘Chimeric’ Genes, Researchers Say", so I of course clicked on it. What followed was very interesting. A couple from Washington used a fertility clinic to help them have a child. The pregnancy and birth went well, but they later found out that the child's blood-type did not match either parent, so they decided to do a paternity test, which the father failed. This lead them to assume that the clinic might have swapped the sperm samples with an unknown donor.

Simply put, a paternity test is done by taking saliva or blood samples from the child, mother, and father(s) in question and comparing the alleles to each other. The child's alleles should have several matches to the mother's and father's, some matches to a non-parent family member, and fewer to none matches to a stranger/non-family member (if the child has no matches, they are probably adopted).


The failed paternity test then led them to do a full DNA test on the father's and child's DNA, after which they found that there was a 10% match, suggesting that he was actually the child's uncle, rather than father. These tests were done using DNA from blood and saliva samples, so doctors then tested his sperm, which contained the match to the child. This phenomenon is called chimerism, which is when a person has extra genes/DNA that were absorbed from an unborn/miscarried twin in the womb. This theory of the man being a chimera supports the uncle results since the DNA in his gametes is ultimately from his unborn brother. Weird, huh?

What if the unborn twin had been a girl? Would that mean that this man's gametes would be eggs, and therefore make him unfertile, or would his sperm contain female DNA that would guarantee that the only children he and his wife could have were girls? The news article I read only mentioned another case where the unborn twin was the same sex as the chimera, so it would be interesting to look into this possible scenario.

Mind Control

Researchers have developed a tiny brain implant that can remotely deliver therapeutic drugs or light pulses to treat certain neurological disorders. They were also able to control certain behaviors, such as turning around in circles. Watch the video below:

I'm not sure how comfortable I am with the idea that someone could inject drugs directly into my brain or stimulate it with an LED light, but the decrease in invasiveness may be appealing to some people. What do you think?

Malaria can be a cure for cancer?!?!

Malaria is bad, right?! Nobody wants malaria. On the other hand, cancer pretty much sucks too. Turns out, the malaria parasite, Plasmodium falciparum, has a protein involved in the parasite's invasive mechanism called VAR2CSA which binds to a specific sugar (Oncofetal chondroitin sulfate) thought to be found only in placental cells, which is why pregnant women have a higher risk for malarial infections. However, cancer cells have been found to also display this sugar. This wasn't too surprising, seeing as how both placental cells and tumor cells have rapid and uncontrollable growth.

Once researchers made this connection, they began developing a way to manipulate the VAR2CSA protein into a drug-delivering vehicle that is specific to tumor cells only so healthy cells are unaffected. In the very recent animal trials, tumors in mice infected with non-Hodgkin's lymphoma shrunk by 75% compared to untreated mice, 33% (2/6) of mice with prostate cancer went into remission, and over 83% (5/6) of mice with stage V breast cancer were completely cured. It will take a few more years to develop a system fully safe and efficient for human trials, but at least there is some hope!

References:

Targeting Human Cancer by a Glycosaminoglycan Binding Malaria Protein

Malaria Protein Could Give Us A Broad Cancer Treatment

DNA - not as easy as GCAT

Almost everyone with a basic knowledge of biology knows that the four primary DNA nucleotides are guanine (G), cytosine (C), adenine (A), and thymine (T). In the 80's a fifth base, methylcytosine (mC), was found and from this discovery, methylation was shown to play a major role in epigenetic changes. However, over the last few years more bases have been discovered and also synthesized, so it is possible that the current DNA alphabet will expand rapidly in the near future.

Naturally or chemically modified bases:

• mA --> methyladenine (known to be in bacteria, but researchers are still trying to see if this exists in mammals)
• 5hmc --> 5-hydroxymethylcytosine
• 5fc --> 5-formylcytosine
• 5cc --> 5-carboxylcytosine

All of these bases can play a role in stem cell research, such as being able to reprogram adult cells into stem-like cells through demethylation. Also, they can be used to reactivate tumor suppressor genes that may have been silenced through methylation in tumor cells.


Engineered bases:

• "Z" --> 6-amino-5-nitro-2(1H)-pyridone
• "P" --> 2-amino-imidazo[1,2-a]-1,3,5-triazin-4(8H)one 

      These bases pair together and can form a double helix just like G-C and A-T pairs and provides the potential to build new proteins for medicinal purposes.


References:
New Nucleotides Identified in Human DNA
Sixth DNA base discovered?
Extra DNA Base Discovered
Structural Basis for a Six Nucleotide Genetic Alphabet

DNA Fingerprinting Using STRs

Genetic testing is an ever-expanding field for scientific and criminal investigations. DNA technology, such as the use of multiplex PCR to analyze short tandem repeats (STRs) – gene segments that are highly polymorphic and are abundant in the non-coding regions of the human genome – has become a new alternative to traditional methods such as southern blots using variable number tandem repeats (VNTRs). VNTRs are also comprised of repeating sequences, but are much longer per repeat (10-100 base pairs vs. 2-9 base pairs) and are generally not as conserved across generations compared to STRs, which makes familial testing more difficult.

The use of STRs for genotyping individuals is commonly known as “genetic fingerprinting” or "DNA profiling". Multiplex Polymerase Chain Reaction (PCR) kits are commercially available, allowing several STR locations (loci) to be amplified and characterized all in one reaction per sample versus several individual reactions of the same sample using regular PCR; this process is quicker and more efficient. The results include the allele patterns for each autosomal locus tested (numbers and locations vary between kits) as well as the Amelogenin locus, which gives the sex of the individual. The more loci you add, the more unique the profile becomes, which is why CODIS uses 13 loci plus the sex marker. Since the small nature of these markers allow them to be more resistant to mutations and degradation, this technique has become highly popular not only for crime scene analysis or paternity testing, but also in the identification of remains from highly traumatic events such as fires, explosions, and airplane crashes, amongst others.

To get a better break-down of this method, watch the video below: