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Maternal effect
A maternal effect is a situation where the phenotype of an organism is determined not only by the environment it experiences and its genotype, but also by the environment and genotype of its mother. In genetics, maternal effects occur when an orga ...
dominant embryonic arrest (Medea) is a
selfish gene composed of a toxin and an antidote. A mother carrying ''Medea'' will
express
Express or EXPRESS may refer to:
Arts, entertainment, and media Films
* '' Express: Aisle to Glory'', a 1998 comedy short film featuring Kal Penn
* '' The Express: The Ernie Davis Story'', a 2008 film starring Dennis Quaid
Music
* ''Express'' ...
the toxin in her germline, killing her progeny. If the children also carry ''Medea'', they produce copies of the antidote, saving their lives. Therefore, if a mother has one ''Medea'' allele and one non-Medea allele, half of her children will inherit ''Medea'' and survive while the other half will inherit the non-Medea allele and die (unless they receive ''Medea'' from their father).
Medea's selfish behavior gives it a selective advantage over normal genes. If introduced into a population at sufficiently high levels, the ''Medea'' gene will spread, replacing entire populations of normal beetles with beetles carrying ''Medea''. Because of this, ''Medea'' has been proposed as a way of
genetically modifying insect populations. By linking the ''Medea'' construct to a gene of interest - for instance, a gene conferring resistance to malaria - ''Medeas unique dynamics could be exploited to drive both genes into a population. These findings have dramatic implications for the control of insect-borne diseases such as
malaria
Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or deat ...
and
dengue fever
Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. Symptoms typically begin three to fourteen days after infection. These may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic ...
.
Construction of Medea
Medea, which has been found in nature only in flour beetles, is the only