Opposites Attract: How Genetics Influences Humans To Choose Their Mates

The MHC(major histocompatibility complexes) is a large genetic region situated on chromosome 6, and found in most vertebrates. It plays an important role in the immune system and also in reproductive success.

Females' preference for MHC dissimilar mates has been shown in many vertebrate species, including humans, and it is also known that MHC influences mating selection by preferences for particular body odours. The Brazilian team has been working in this field since 1998, and decided to investigate mate selection in the Brazilian population, while trying to uncover the biological significance of MHC diversity.

The scientists studied MHC data from 90 married couples, and compared them with 152 randomly-generated control couples. They counted the number of MHC dissimilarities among those who were real couples, and compared them with those in the randomly- generated 'virtual couples'.They would have expected to see similar results from both sets of couples. But they found that the real partners had significantly more MHC dissimilarities than they could have expected to find simply by chance.

Within MHC-dissimilar couples the partners will be genetically different, and such a pattern of mate choice decreases the danger of endogamy (mating among relatives) and increases the genetic variability of offspring. Genetic variability is known to be an advantage for offspring, and the MHC effect could be an evolutionary strategy underlying incest avoidance in humans and also improving the efficiency of the immune system, the scientists say.

Reference:
http://www.sciencedaily.com/releases/2009/05/090525105435.htm

Genes May Determine Success of Hip Replacement Surgery

Out of a sample of 312 patients who had undergone hip replacement surgery, 162 suffered complications 10 years later. To test if certain genetic variations were responsible for the success of this surgery, DNA samples were taken from from all participants. It was discovered that patients with variations in MMP1 (matrix metalloproteinase 1- an enzyme that breaks down collagen, the main protein in bone) were more than three times as likely than patients lacking the variation to develop "aseptic loosening", a condition where the artificial joint loosens and the surrounding bone starts to disintergrate. In addition, genetic variations concerning the vitamin D receptor gene (vitamin D is necessary for strong, healthy bones) doubled a patient's chance of deep infection.

The researchers concluded that with further research these findings could help predict the long-term success of hip replacement surgery as well as develop targeted genetic treatments.

Link: http://www.sciencedaily.com/releases/2007/03/070314195704.htm

Opposites Attract: How Genetics Influences Humans To Choose Their Mates

Researchers have found that females often prefer mates with dissimilar major histocompability complex(MHC) in many vertebrate species, including humans, and that the MHC influences mating selection by preference for particular body odors.

The Brazilian team has been working in this field since 1998, and decided to investigate mate selection in the Brazilian population, while trying to uncover the biological significance of MHC diversity.

The scientists studied MHC data from 90 married couples, and compared them with 152 randomly-generated control couples. They counted the number MHC dissimilarities among those who were real couples, and compared them with those in the randomly-generated 'virtual couples'. If MHC genes did not influence mate selection, they would have expected to see similar results from both sets of couples. But they found that real partners have significant more MHC dissimilarities than they could have expected to find simply by chance.

The MHC is a large genetic region situated on chromosome 6, and found in most vertebrates. It plays an important role in the immune system and also in reproductive success.

Within MHC-dissimilar couples the partners will be genetically different, and such a pattern of mate choice decreases the danger of endogamy (mating among relatives) and increases the genetic variability of offspring. Genetic variability is known to be an advantage for offspring, and the MHC effect could be an evolutionary strategy underlying incest avoidance in humans and also improving the efficiency of the immune system, the scientists say.

Gene Therapy Effective Treatment against Gum Disease

ScienceDaily (Dec. 13, 2008)

Scientists at the University of Michigan have shown that gene therapy can be used to stop the development of gum disease such as periodontal disease. Gene therapy has not been used in non-life threatening disease. They were the first to use gene transfer to show potential in treating chronic conditions. The Seattle-based biotechnology company Targeted Genetics had carried out a human trial and the results showed that the same gene therapy approach had positive affects in human patients with rheumatoid arthritis.

An inactivated virus was used to produce more of a molecule called tumour necrosis factor receptor in certain cells. It is able to reduce the excessive levels of tumour necrosis factor which is a molecule known to cause bone destruction such as rheumatoid arthritis, joint deterioration and periodotitis. The periodontal tissues were spared from destruction by more than 60 to 80 percent with the use of gene therapy and the delivered gene keeps producing in the cells for a very long period of time.

Reference:
http://www.sciencedaily.com/releases/2008/12/081211081448.htm

In pubs, clubs, homes and parks all around the world, it is a common site to see people getting “boozed”. However scientists at the University of California may have found a solution for such mayhem. They have found a gene (aptly named happyhour) in the fruit fly genome, which when mutated away from the norm, allowed the flies to drink more alcohol without feeling the effects of it, as compared to regular fruit fly. When the flies gene was turned back on, their ability to tolerate alcohol was reduced to the normal accepted level among their fruit fly peers. It’s also been noted that this gene dampens a cellular network (epidermal growth factor or EGF) which has been implicated in cancer.

Drugs that also inhibit this network were tested on the flies and mice, and it was found that when on these drugs, the animals were more likely to not party hard and would not make it through the night. That is they were more affected by the alcohol that regularly. Surprisingly when such drugs were given to rats, they managed to control their urges and drank less alcohol. It’s believe that this may be related to dopamine and serotonin levels. This could lead to future treatments for alcoholics who can’t quit and provide a medical treatment to inhibit their addictions. The drugs which have before been tested on people for other reasons have shown to have little side effects, besides a skin rash.
References:
• http://www.newscientist.com/article/dn17178-happyhour-gene-may-help-put-boozers-off-their-drink.html - 'Happyhour' gene may help put boozers off their drink - health - 21 May 2009 - New Scientist – 25/05/09
• Corl et al., Happyhour, a Ste20 Family Kinase, Implicates EGFR Signaling in Ethanol-Induced Behaviors, Cell (2009), doi:10.1016/j.cell.2009.03.020

Breast Cancer Genes

RASSF1A Polymorphism A133S Is Associated with Early Onset Breast Cancer in BRCA1/2 Mutation Carriers

http://cancerres.aacrjournals.org/cgi/content/abstract/68/1/22

Author: Ashley St John

This article is about a small-scale initial study that was testing for a correlation between RASSF1A polymorphism A133S and an early onset of breast cancer in BRCA1/2 mutation carriers. The study shows a positive correlation in people who develop breast cancer through a BRCA1/2 mutation and the RASSF1A A133S polymorphism gene. This study also showed a higher frequency of the A133S gene in people who had family history of breast cancer.

The study showed that people who had the A133S gene and the BRCA1/2 mutation had an earlier onset of breast cancer. It also showed that people who did not have the mutation but did have breast cancer also had the A133S gene. This preliminary study produced interesting results and warrants and larger study to show how strong the correlation between A133S and breast cancer.

The Cloning of Dead Mice

Teruhiko Wakayama a genetic scientist from the RIKEN Center for Developmental Biology in Kobe, Japan led a team in a special mice cloning project that involved cloning mice that had been frozen for 16 years. The reason this is such a breakthrough is because this opens up the possibility of being able to clone long since extinct animals. The way this cloning process is done is by injecting the nucleus of a thawed out dead mouse tissue cell into a mouse egg with its nucleus removed. During their experiment the Wakayama team found that the easiest way to close the mice was by using some brain tissue this is quite a remarkable discovery as brain tissue has never been used for cloning. According to Wakayama freezing and thawing the tissue cells is the most effective way to clone the mice as it allows for an easy ‘reprogramming’ of the brain cell nucleus.

George Lukin

http://www.newscientist.com/article/dn15111-cloning-resurrects-longdead-mice.html