Smanjenje Y kromosoma u evoluciji kariotipa čovjeka

undergraduate thesis

• Title (english): Reduction of Y chromosome in evolution of human karyotype
• Author: Sonja Šogorić
• Mentor: Mirjana Pavlica (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2010, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Y kromosom već dulje vrijeme zaokuplja pažnju u znanstvenim krugovima, prvenstveno zbog njegove uloge u spermatogenezi i determinaciji muškog spola koja ovisi o razvitku testisa, čija diferencijacija ovisi o Y kromosomu. Jedinstven je po tome što sadrži samo nekoliko aktivnih gena i mnogo pseudogena koji se ne prepisuju u produkt (protein ili RNA). Pretpostavka o evoluciji Y kromosoma je da se smanjuje, gubi funkcionalne gene i da bi mogao nestati za nekoliko milijuna godina. Nedavna interspecijska istraživanja su pokazala da je evolucija ljudskog Y kromosoma mnogo brža od ostatka genoma (prvenstveno zbog prijenosa Y kromosoma samo muškom linijom) što je zajedno s nedostatkom rekombinacije dovelo do smanjenja Y kromosoma, odnosno do gubitka gena pozicioniranih na Y kromosomu. Jedna pretpostavka govori o Y kromosomu kao o geniju, dominantnom kromosomu koji determinira muške jedinke, o sebičnom Y kromosomu koji privlači gene (uz faktore rasta) odgovorne za nastanak mužjaka. Drugi model prikazuje Y kromosom kao mekušca i slabića, sjenu samog sebe kakav je nekada bio, degradirajući u gotovo ništa. Uspoređivanjem Y kromosoma čimpanze i čovjeka uočeno je da se njihovi Y kromosomi razlikuju u strukturi i sadržaju gena u vrlo velikom postotku, za razliku od ostalog genoma, u kojem je uočena velika podudarnost. Ova činjenica ukazuje na ubrzanu evoluciju i velike strukturne promjene Y kromosoma (i čimpanze i čovjeka) u zadnjih 6 milijuna godina, nakon divergencije dvije evolucijske linije. Istraživanja na ovom području se nastavljaju; znanstvenici se nadaju da će uspjeti odrediti kada će točno Y kromosom nestati te koji su procesi najzaslužniji za smanjenje Y kromosoma.

Abstract (english)

Y chromosome has been occuping attention in scientific community for a long time, primarily because of its role in spermatogenesis and sex determination that depends on the testes, which differentiation depends on the Y chromosome. It is unique because it contains only a few active genes and many pseudogenes that are not transcribed in the product (protein or RNA). The assumption about the evolution of the Y chromosome is that it becomes smaller, loses functional genes and could disappear in a few million years. A recent interspecies studies have shown that the evolution of the human Y chromosome is much faster than the rest of the genome (mainly due to the transfer of the Y chromosome only through male line) and along with a lack of recombination led to a reduction of the Y chromosome, or loss of genes positioned on the Y chromosome. One hypothesis speaks about the Y chromosome as a genius, the dominant chromosome that determines male individuals, of selfish Y chromosome that attracts genes (with growth factors) responsible for male development. The second model shows the Y chromosome as wimp and weakling, a shadow of itself as it once was, degrading in almost nothing. Comparison of chimpanzee and human Y chromosome have shown that their Y chromosomes differ in structure and content of genes in a very large percentage, in contrast to other genes which show a great match. This fact indicates a rapid evolution and major structural changes in Y chromosome (and chimps and humans) in the last 6 million years, after the divergence of two evolutionary lines. Research in this area continue; scientists hope to be able to determine exactly when will Y chromosome disappear, and which processes are most responsible for the reduction of the Y chromosome.

• Keywords: Y kromosom
• Keywords (english): Y chromosome
• Language: croatian
• URN:NBN: urn:nbn:hr:217:024947
• Study programme: Title: Molecular Biology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) molekularne biologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) molekularne biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-04-04 09:59:30