There is virtually no part the human body that does not contain DNA. Every portion in our body that contains cells has this genetic code. The only exception to this is the red blood cells which have no nucleus on them. So any cell with a nucleus carries DNA.
DNA can be extracted from bodily fluids
that are of potential forensic value. The extracted DNA material can be analysed by forensic experts as evidence into linking suspects to a particular crime. The list below provides insight into bodily fluids that carry DNA which is a great tool in forensic investigations.DNA can be extracted from bodily fluids
1. Saliva
DNA is present in sufficient amount to be detected and extracted no matter the smallness in the sample.
As we speak, spurts of saliva in from our mouth are let out in tiny droplets. Sometimes we are unaware of them.
In the movie series Forensic Files a serial rapist Chad Price was arrested convicted based on the DNA gotten from the soft drink can that he was given to drink during questioning. The DNA obtained from the can was compared with the DNA extracted from the semen found on the rape victims. He never suspected he ever can be caught. He was imprisoned for life. Yes, saliva got him sent him to prison for life!
DNA is present in sufficient amount to be detected and extracted no matter the smallness in the sample.
As we speak, spurts of saliva in from our mouth are let out in tiny droplets. Sometimes we are unaware of them.
In the movie series Forensic Files a serial rapist Chad Price was arrested convicted based on the DNA gotten from the soft drink can that he was given to drink during questioning. The DNA obtained from the can was compared with the DNA extracted from the semen found on the rape victims. He never suspected he ever can be caught. He was imprisoned for life. Yes, saliva got him sent him to prison for life!
2. Semen
Semen otherwise known as seminal fluid is contains sperm cells.
Fact
It is possible for sperm cells to be absent in a semen. A male whose vans deference has been surgically tied or cut will not emit sperm cells in his semen. Its called vasectomy or male sterilization.
DNA present in sperm cells is different from that found in seminal fluid.
Thus any DNA found in semen is of potential forensic importance which can serve as evidence to convict a suspect.
Semen otherwise known as seminal fluid is contains sperm cells.
Fact
It is possible for sperm cells to be absent in a semen. A male whose vans deference has been surgically tied or cut will not emit sperm cells in his semen. Its called vasectomy or male sterilization.
DNA present in sperm cells is different from that found in seminal fluid.
Thus any DNA found in semen is of potential forensic importance which can serve as evidence to convict a suspect.
3. Blood
In this case the white blood cells and platelets are the materials of interest since red blood cells do not contain DNA.
Therefore scientific methods are employed to separate the white blood cells and platelets from the whole blood sample obtained either from an individual or a crime scene.
Blood sample collected from crime scene may be in small quantities and spatters. Can DNA be extracted from dried blood samples? Yea. Its just dried. FACT: Blood sample can be recovered from any piece of cloth that had blood stains on it and was washed clean. Wow!
So even if you wash off blood stains from a cloth 100 times with soap and water (plus hypo) until it becomes 'pure white'....ever heard of luminol?
In this case the white blood cells and platelets are the materials of interest since red blood cells do not contain DNA.
Therefore scientific methods are employed to separate the white blood cells and platelets from the whole blood sample obtained either from an individual or a crime scene.
Blood sample collected from crime scene may be in small quantities and spatters. Can DNA be extracted from dried blood samples? Yea. Its just dried. FACT: Blood sample can be recovered from any piece of cloth that had blood stains on it and was washed clean. Wow!
So even if you wash off blood stains from a cloth 100 times with soap and water (plus hypo) until it becomes 'pure white'....ever heard of luminol?
4. Urine
DNA from my pee? Of course. Urine contains water, urea, minerals even blood cells (which is not normal) which passes through the urethra...I mean the canal through which urine flows from the body out. The materials found in urine "rub shoulders" with your liver, kidney, intestines in your body system. And these organs are DNA packed which sort of thumb print their signature on the passerby fluids.
SIGNIFICANCE.
Urine sample gotten from a crime scene, suspect or victim can be analysed for DNA which is of potential forensic value.
DNA from my pee? Of course. Urine contains water, urea, minerals even blood cells (which is not normal) which passes through the urethra...I mean the canal through which urine flows from the body out. The materials found in urine "rub shoulders" with your liver, kidney, intestines in your body system. And these organs are DNA packed which sort of thumb print their signature on the passerby fluids.
SIGNIFICANCE.
Urine sample gotten from a crime scene, suspect or victim can be analysed for DNA which is of potential forensic value.
5. Sweat
This secretion from the sweat glands contain enough DNA for analysis. Its generally contains water and other materials called electrolytes which are produced from the blood. Nerves control sweating.
FACT Emotionally induced sweating is that's restricted to palms, soles of feet and foreheads.
In 2013, a man burgled a house, stole their TV and escaped. He was later caught. His sweaty footprints were left on the floor. He obviously was barefooted when he entered the home and was sweating on his feet! The sweat print sample was analysed for DNA and compared with a database and there was a match! (Wear shoes next time)
This secretion from the sweat glands contain enough DNA for analysis. Its generally contains water and other materials called electrolytes which are produced from the blood. Nerves control sweating.
FACT Emotionally induced sweating is that's restricted to palms, soles of feet and foreheads.
In 2013, a man burgled a house, stole their TV and escaped. He was later caught. His sweaty footprints were left on the floor. He obviously was barefooted when he entered the home and was sweating on his feet! The sweat print sample was analysed for DNA and compared with a database and there was a match! (Wear shoes next time)
6. Tears
The cilliary glands are responsible for producing tears. Aside water and chemicals, shed cells ( dead cells that tissue organs dump) are deposited into bodily fluids. Shed cells contain DNA....even when dead just as sperm cells are dead after their heads separate from their tails, but their DNA is still retained.
So it is the DNA from the shed or loose cells that is extracted as DNA evidence in a court of law. Studies have backed the presence of DNA in harvested tears. Yea...when you cut onions and your eyes get watery what are you doing....?
Harvesting tears. I am yet to see or hear about a conviction from 'tears evidence'. Its possible.
The cilliary glands are responsible for producing tears. Aside water and chemicals, shed cells ( dead cells that tissue organs dump) are deposited into bodily fluids. Shed cells contain DNA....even when dead just as sperm cells are dead after their heads separate from their tails, but their DNA is still retained.
So it is the DNA from the shed or loose cells that is extracted as DNA evidence in a court of law. Studies have backed the presence of DNA in harvested tears. Yea...when you cut onions and your eyes get watery what are you doing....?
Harvesting tears. I am yet to see or hear about a conviction from 'tears evidence'. Its possible.
7. Sebum
These are waxy oils that are secreted in our ears, palms, feet etc.
Fact Its the waxy oils in our palms that makes it possible for our fingerprints be to developed.
Sebum can be analysed for genomic material which makes it of potential forensic value. Ear wax is no different as well.
These are waxy oils that are secreted in our ears, palms, feet etc.
Fact Its the waxy oils in our palms that makes it possible for our fingerprints be to developed.
Sebum can be analysed for genomic material which makes it of potential forensic value. Ear wax is no different as well.
8. Stomach Contents
That's my euphemistic way of calling vomit. But in order not to get so messy about it, I will explain it like this:
Fact Before the we eat becomes useful to us, some fluids known as digestive juices must act on food materials. These juices are present in our stomachs now. They are produced by our body tissues specialized in digestion. If you're into science a bit, how does concentrated HCl end up in our stomachs? Nobody takes conc HCl and exclaims... "Wow, this is cool".
As earlier stated, our body constantly gets rid of dead cells and are replaced by new ones. These dead cells are 'shed' into the system to be flushed out. They take many routes to get out such as sweat, faeces, urine, blood etc.
Therefore expect shed cells interaction with food fragments in your stomach. Fact II Shed cells are DNA packed. Your stomach content can be a potential source of DNA.
That's my euphemistic way of calling vomit. But in order not to get so messy about it, I will explain it like this:
Fact Before the we eat becomes useful to us, some fluids known as digestive juices must act on food materials. These juices are present in our stomachs now. They are produced by our body tissues specialized in digestion. If you're into science a bit, how does concentrated HCl end up in our stomachs? Nobody takes conc HCl and exclaims... "Wow, this is cool".
As earlier stated, our body constantly gets rid of dead cells and are replaced by new ones. These dead cells are 'shed' into the system to be flushed out. They take many routes to get out such as sweat, faeces, urine, blood etc.
Therefore expect shed cells interaction with food fragments in your stomach. Fact II Shed cells are DNA packed. Your stomach content can be a potential source of DNA.
9. Menses
Studies have shown that what is passed out during menstruation is actually made up of pathogens, dead sperms(if sexually active), uterus lining, unfertilized eggs etc. Quite a resource bank for DNA isn't it? All of these are made up of dead cells and dead cells do NOT lose their genetic coding. The DNA portion in them are never lost nor degraded under normal conditions.
Studies have shown that what is passed out during menstruation is actually made up of pathogens, dead sperms(if sexually active), uterus lining, unfertilized eggs etc. Quite a resource bank for DNA isn't it? All of these are made up of dead cells and dead cells do NOT lose their genetic coding. The DNA portion in them are never lost nor degraded under normal conditions.
10. Mucus
As a forensic scientist and crime scene investigator, never rule anything out in a crime scene. Sources of mucus can be nostrils, vagina, wounds. Any opening in the human body has the potential to secrete mucus depending on the condition. They are produced by the body either as a means of excretion or induced by certain hormones(in the case of the female physiology).
As a forensic scientist and crime scene investigator, never rule anything out in a crime scene. Sources of mucus can be nostrils, vagina, wounds. Any opening in the human body has the potential to secrete mucus depending on the condition. They are produced by the body either as a means of excretion or induced by certain hormones(in the case of the female physiology).
Also useful to note is the fact that not all bodily fluids contain sufficient information to gain a DNA comparison. This happens when the individual is what is described as a 'non-secretor'. A 'non-secretor' will hey not have sufficient levels of protein in their bodily fluids to determine a match between blood and bodily fluids found at a crime scene. Of course the percentage of 'non-secretors' among the populous as opposed to 'secretors' is very small indeed. CB Dolph
ReplyDeleteI agree with you Dolph...its very possible. They are very rare humans though. I have seen cases were insufficient protein levels lead to inconclusive DNA analysis. The str-pcr based machines are very sensitive to the minutest of protein content. It can detect and analyze even dried semen patches!
ReplyDelete