You may have learned in school that human race have 23 pairs of chromosomes : 22 “ autosomes ” and their partners , which contain passably much the same genes and in the same Holy Order , plus one pair of sex chromosomes that conduce to the differentiation in sexual trait . But enough about us . The Amazonian Leptodactylus pentadactylus ( smoky hobo camp frog ) has six duet of sex chromosomes .
A team of investigator in Brazil made this realization with several lines of evidence , mention that this toad frog ’s sex chromosomes demand a whole different manner of get offspring . Plus , it ’s disc - break .
“ The number of sex chromosome is larger than the number of autosomes found , and these data represent the large number of multiple sex chromosomes ever retrieve among vertebrate mintage . ” the authors spell in the cogitation bring out recently in the journal Chromosoma . This breaks the record previously held by the platypus , which has 10 gender chromosome , 5 X and 5 Y.
The researcher taper out that sex conclusion organization have evolve separately in different groups . In humans , materialization normally experience two couple of ten chromosomes or an X and a Y. The presence of a Y chromosome releases a hormone telling the body to develop a penis and testes ( and so on ) instead of a vagina and ovaries . In birdsand other species it works the opposite way of life : there ’s either ZZ or ZW , where the W signifies that the hoot is going to lay egg .
But things bring way otherwise with these frogs . scientist analyse their deoxyribonucleic acid and find six “ X ” and six “ Y ” chromosomes in males , and twelve “ X ” chromosome in females . They also inserted a special fluorescent fixture investigation that binds to the desoxyribonucleic acid , and look out the cells get ready to replicate .
Again , remember us humans : Most of our cell have 46 chromosomes ( 23 pairs ) . spermatozoan and ballock cellphone are formed through a procedure called “ litotes , ” which results in those pairs separating . Babies develop when the sperm cell cell and the ballock cellphone combine , each land 23 unmarried chromosome to the party ( the egg has an “ X , ” and the sperm can have an “ X ” or a “ Y ” ) .
So how does it cultivate with six pairs of sex activity chromosome ? In males , the Xs and Ys align in an “ astonishing stable doughnut - shaped meiotic chain ” of chromosomes , which arranges itself so that when the cubicle divide , the right gametes form with the correct chromosomes .
“ This is really out of doors what we suppose is ‘ normal ’ meiosis , ” investigator Tony Gamble from Marquette University in Wisconsin , told me in an electronic mail . “ I ’m worked up about the paper because it show just how incredibly weird sex chromosomes can be . Just when you think you ’ve determine the uncanny thing imaginable — like the platypus and its 5X5Y system — along comes something even uncanny . It also suggest this meiotic chain system may not be as rarefied as we imagine and should encourage scientist to explore sex activity chromosomes in a greater diversity of coinage . ”
He noted that the paper was mostly data-based — the challenge will be really forecast out the organic evolution of these systems . “ Understanding how these organization develop and are defend is a dissimilar story though and will in all probability prove much harder to envision out . ”
Dang , evolution . You remain to mix up .
[ Chromosoma ]
BiologyBirdsEcologyfrogsScience
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