Originally posted by caz
View Post
Announcement
Collapse
No announcement yet.
a6 murder
Collapse
This topic is closed.
X
X
-
Originally posted by Steve View PostAre you quite sure it was Churchill and not WC Fields?Kind regards, Sam Flynn
"Suche Nullen" (Nietzsche, Götzendämmerung, 1888)
Comment
-
Originally posted by Steve View Post'You are drunk!
'And you are ugly, but in the morning I'll be sober, and you'll still be ugly!'
I think it was a Carry-On film with Frankie Howerd, but I could be wrong!
and he was not the messiah just a naughty boy so b****r off!
Reg
Comment
-
Originally posted by caz View PostTony,
Why is any of this relevant, if they found semen at the time that belonged to someone of a different blood group from JG's? This must have come from the rapist, and it beggars belief that every last trace of it could have disappeared over the years from the retained knicker fragment, only to be replaced by an innocent JH's DNA, which had somehow managed to contaminate the fragment instead.
From issue 2594 of New Scientist magazine, 07 March 2007, page 16
Police investigating sexual assaults could be aided by a new technique that allows DNA to be collected from semen samples even when no sperm are present.
A common problem for forensic scientists hoping to use DNA fingerprinting to identify assailants in sexual assault cases is that the quantity of male DNA in swabs taken from the woman is often tiny compared to the amount of hers present. "The female DNA profile is so strong in the analysed sample that the male DNA is swamped," says Andy Hopwood of the Forensic Science Service in Birmingham, UK. This means that conventional methods of amplifying small amounts of DNA don't work, because the female DNA would be amplified as well. "We're looking for ways to isolate out the male component," Hopwood says.
One way of doing this is using a method called preferential lysis, in which enzymes are used to destroy the membranes of ordinary cells, leaving only the more robust sperm cells behind. However, in some cases the assailant may not produce any sperm - either because of a medical condition or because he has had a vasectomy.
"It is surprisingly common," says Hopwood. "The semen may have come from a vasectomised male in around 10 to 15 per cent of the cases we deal with. We got to thinking: 'What else is there in this sample that we could look for?'"
Semen doesn't only contain sperm, but often immune and epithelial cells as well. Until recently, these would have been virtually impossible to distinguish from female cells present in a swab. Now Hopwood's team has done just that by combining a technique called laser microdissection (LMD), which enables single cells to be extracted from a microscope slide, with fluorescence in-situ hybridisation (FISH), a method that can be used to highlight chromosomes carrying a particular DNA sequence.
Hopwood's team used fluorescent tags specific to repetitive areas of DNA on the X and Y chromosomes. When added to cells and viewed under a fluorescence microscope, these tags made the X chromosomes glow red and the Y chromosomes green. This made it possible to distinguish between male cells containing an X and a Y chromosome, and female cells containing two X chromosomes.
The team then used LMD to mark the coordinates of male cells on a microscope slide and cut them out from the plastic membrane they were sitting on. The researchers transferred the cells to a collecting tube and used DNA amplification to increase the amount of male DNA. They were then able to compare the DNA against a database of DNA profiles in order to search for the assailant.
Using this technique, full male DNA profiles have so far been obtained from vaginal swabs taken up to 24 hours after sexual intercourse, even when no sperm were present.
The FSS gets around 90 cases a year in which the new technique could be useful, says Keith Elliott, one of Hopwood's team. "These are really difficult cases where you have a sample that's semen positive, but sperm negative," he says. In January, the technique was put into practice for the first time, helping UK police to charge a suspected rapist when his DNA profile was found to match the male DNA recovered from the victim. The case is currently going through the UK courts.
James
x
Comment
-
James Dean
Good morning terrier!
I haven't got time to go into the science at the moment so I'll just take your sentence - "So if the rapist had no sperm in his semen, the DNA would not have to disappear because it would never have been present in the first place"
The article doesn't say that there is no DNA present in the semen, it says that it is there, but they have difficulty detecting it.
The arguement is fundamentally the same as the one regarding somebody else's DNA on the portion of the knickers not tested; yes it's a possibility but it still doesn't account for the DISTRIBUTION of JH's DNA.
All the best
johnl
Comment
-
[QUOTE=Graham;38124]Hi Tony,
So dear Mrs Lanz could recall, out of all the customers she had that night, what MG and VS were drinking? Yeah?
Hang on a minute Graham,
Imagine yourself as a pub landlord in 1961. I don’t know how busy the pub is but you have two regulars a man and a young woman who have been there on occasions before you might be on speaking terms or nodding terms I don’t know.
You wake up next morning to the news that this couple have both been shot. You don’t just instantly forget about it you would be talking to your partner/staff about it. In fact you would probably talk about nothing else. “Oh her hair was different last night, she was wearing a green blouse, and I don’t think they were drunk. What were they drinking? Oh yes that’s right Double Diamond and gin and pepsi cola. Yes don’t sell too many of those do we? What time did they leave? That’s right 9.20. Yes just before that other bloke with the brown eyes and slicked back hair. He’s been in before when they have I wonder if he knows what’s happened.”
Tony.
Comment
-
Originally posted by Steve View PostTony
She remembered some time afterwards, when prompted by Jean Justice!
KR
Steve
I still say that if you were serving someone in the pub and next day you found out they had both been shot you would think of nothing else but that previous evening and about the shot couple. You simply wouldn’t be able to help yourself. Things like “Oh yes what a nice bloke always very polite bit of a charmer. He wore a wedding ring but I don’t think the girl was his wife. He always drank DD but she liked a change Do you know where they come from? Do you know if they are local? Did they ever come in with anyone else? Do you remember the time they etc etc?
You would be racking your brains for bits of memories.
It’s just the same as when an acquaintance or relative dies somebody tells a tale that everyone has forgotten but suddenly everyone has a new tale to tell.
Tony
Comment
-
Hi Tony
Apparently the couple left the pub when it began to fill up with customers. I think I'm right in saying that Mary Lanz was serving on her own that evening, and I believe that would have been the case because Tuesday evening is widely regarded as the landlord's night off. Tuesday is usually the quietest evening of the week for pubs.
KR
Steve
Comment
-
Originally posted by Tony View PostMorning Steve,
I still say that if you were serving someone in the pub and next day you found out they had both been shot you would think of nothing else but that previous evening and about the shot couple. You simply wouldn’t be able to help yourself. Things like “Oh yes what a nice bloke always very polite bit of a charmer. He wore a wedding ring but I don’t think the girl was his wife. He always drank DD but she liked a change Do you know where they come from? Do you know if they are local? Did they ever come in with anyone else? Do you remember the time they etc etc?
You would be racking your brains for bits of memories.
It’s just the same as when an acquaintance or relative dies somebody tells a tale that everyone has forgotten but suddenly everyone has a new tale to tell.
Tony
Morning again Steve,
And also don’t forget this was midweek. The pub probably wasn’t all that busy.
One thing though do you know if VS and MG went into the pub with anyone else?
Tony
Comment
-
Originally posted by Steve View PostI would have thought they would have wanted to be alone, so it's unlikely they were with anyone else. I've never read anything other than that they were alone.
I quote from ‘Real-Life Crimes and how they were solved’ vol 2 part 27 published weekly.
Sorry Steve it hasn’t got the date on it but it was published by Eaglemoss Publications Ltd 2003 and it has email addresses etc so it’s fairly new.
Quote:
“Within hours, the police were taking a detailed statement from the surviving victim, Valerie Storie had been rushed to Bedford General Hospital for emergency treatment. But despite clearly suffering pain and distress, she was able to give Detective Sergeant Douglas Rees a remarkably lucid account of her ordeal.
‘We left home at 7.45pm and went for a drink at the Old Station Inn with friends of Mike’s. At 9.30 we went to Dorney Common and it was at this time we were approached by the man’.
I think you can still get a copy. There is a particularly good photo of Louise Anderson in it and lots of other stuff.
Tony.
Comment
-
Originally posted by johnl View Post[B]
The article doesn't say that there is no DNA present in the semen, it says that it is there, but they have difficulty detecting it.
The arguement is fundamentally the same as the one regarding somebody else's DNA on the portion of the knickers not tested; yes it's a possibility but it still doesn't account for the DISTRIBUTION of JH's DNA.
The article is saying that in normal circumstances they have difficulty detecting the male DNA as it gets swamped by a much larger amount of female DNA. Where sperm is not present in semen then they were unable to detect male DNA at all prior to the advent of the latest technique for recovering DNA from immune and epithelial cells. It follows, therefore, that the 2002 tests in this case would not have recovered any DNA from a male who had deposited semen on the garment in question if that semen did not contain any sperm.
I am presenting a plausible explanation for why the killers DNA could possibly not have shown up in those tests. The question then follows as to how JH DNA did show up and the answer to that has to be contamination. We only need a single cell from JH to be present in the test for it to be confirmed as a positive match after it has been effectively photo copied by the PCR process.
As to your 'distribution of JH's DNA', I think that's a spurious argument. There would have been staining on the garment consistent with what was alleged to have happened but can you say that all the male DNA present in the stains is that of JH? I don't think you can be sure of that. The test doesn't reveal the presence of specific DNA at specific points on the garment, it merely reveals the sum total of all DNA found on the fragment used in the test. Returning to the question of 'what if the rapist had no sperm in his semen' then you can still get the result of JH DNA being detected and the rapist not showing up.
It's a technical argument and I doubt if we shall ever find out if this is a real possibility. Did the forensic people know if sperm was present or not? Did they care in 1961? That it was semen belonging to a male with a particular blood group type seems to be all they were interested in. I'm sure that by 2002 it was impossible to know if sperm had been present or not. All we have is a stain on a tiny fragment of material.
Regards
James
Comment
Comment