The birth of an organism usually takes an egg and a sperm; the sperm needs to be fused with the egg in order to help develop it into a zygote for the formation of an offspring and then the birth of a child leads thereafter. These two factors are essential for life and for the recent decades their origin esp. of the sperm has been an interesting question which has led many studies on the origin and evolution of the factors that lead to production of sperms.
The sperms are basically stored in the male genitalia testicles and a recent study by Eugene Xu, assistant professor of obstetrics and gynaecology at Feinberg reveals that a gene 'Boule' seems to be responsible for their production. Boule is the one gene that is responsible for sperm production and has remained unchanged ever since the evolution. North-western scientists also discovered in their research that Boule appears to be the only gene known to be exclusively required for sperm production from an insect to a mammal. This is the first clear evidence that suggests the ability of males to produce sperm is very ancient, typically & probably originating at the dawn of animal evolution 600 million years ago. This finding suggests that all animal sperm production likely comes from a common prototype. [Eugene Xu, Plos genetics]. Boule is most likely to be the oldest human sperm-specific gene ever discovered. Human gene was discovered originally in 2001 by Xu. When Xu's research group knocked out the Boule gene from a mouse, the animal appeared to be healthy but did not produce sperm. His work suggests that disrupting the function of Boule or knocking it out in animals most likely will disrupt their breeding and put the threatening parasites or germs under control. To support the hypothesis that this gene Boule is widespread in all those animals that produce eggs and sperm, a sea anemone was taken under the study, which is an ancient animal. After obtaining its sperm, tests were run to detect the presence of Boule. After the Boule's presence had been determined in the sea anemone, the theory was established that the Boule gene plays a key role in producing sperms almost in all the organisms and has maintained its function since the evolution. Most of the features in the process of sexual reproduction are conserved or at least they seem to be so. The DAZ gene family in Homo sapiens is one such feature. It mainly consists of a Y-linked DAZ gene, an autosomal DAZ-like gene (DAZL) and BOULE genes. They all appear to share a conserved RNA recognition motif and a DAZ repeat consisting of amino acid repeats that are 24 in number and rich N, Y & Q residues. Although no mutation in BOULE has been observed as to be the cause of infertility in men but all the DAZ proteins are reproduction-linked and the DAZ gene has been shown to be deleted or non-existent when a men has no or few sperms.
Disruption of function: To determine the effect of Boule on the sperm producing requirements of the animals belonging to bilateral phyla, several experiments were conducted and mouse was chosen as a test organism and representative of deuterostome species. Using gene targeting, the RRM domain was deleted and the function of mouse Boule was disrupted. Exon 3 was replaced with a lac z neo vector by homologous recombination in embryonic stem cells which caused the deletion of RNA binding motif and a frame shift in the transcript. Four chimeric mice were recovered and the germ line transmission along with homologous recombination was confirmed. However, the absence of wild type Boule transcripts was confirmed through RT-PCR in the heterozygotes, and instead a much larger PCR product containing the lac-Z gene from the knockout vector was found to be present. This research yielded the result that the function of Boule is completely disrupted in its mutants.
Male Contraception: As the disruption of a gene or a mutation in it, effects only its own function and doesn't in any way reflect its consequences on other genes and their functions, tissues, bodily organs etc., similarly the disruption or deletion in Boule homolog disrupt its own function only. By utilizing these findings, more effective male contraceptive pills can be designed that would be specific to their target that is the boule gene. By directly targeting the boule gene, its function will be disrupted more effectively and thus the contraceptive issues can be resolved. It can be done either by the two methods viz. permanently deleting the boule gene for the lifelong contraception or temporarily disrupting the expression and function of boule for the time-being leading to child birth control and a remarkable approach for male contraception.
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A Budding biotechnologist + writer from India.. Visit http://in.linkedin.com/pub/shivani-sharma/4b/91b/384 for more details
Researcher ID- J-4200-2012