CROMOSOMA Y PDF
CROMOSOMA Y PDF!
Se analizaron haplotipos STR del cromosoma Y (8 loci) en afrodescendientes y caucásico-mestizos no relacionados de Colombia, para correlacionar el. Cromosoma-Y. 3 likes. Ropa Exclusiva para Hombres. Las microdeleciones del cromosoma Y representan una causa importante de infertilidad masculina descrita recientemente. Su estudio podría explicar la.
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It is the molecular "switch" that determines sex in humans Y Chromosome Genes Human Y chromosome SRY Sry sex-determining region on the Y chromosome gene was found cromosoma y on cromosoma y Y chromosome and the first Sox gene identified, the sry gene encodes a "testis-determining factor" a aa protein Mr Da.
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Sry acts as a transcriptional activator HMG type-high mobility group binding to DNA and initiating male sex determination then regulating male development.
The protein sequence is shown on this current page and the full genebank entry can also be seen. Read about the cromosoma y of the testis determining factor which is SRY.
The actual gene targets of SRY are still being determined but at least one downstream gene Sox9 has been identified.
Y Chromosome - Embryology
Another gene Dax1 nuclear hormone-receptor superfamily member when expressed as a transgene will antagonize Sry and also cromosoma y dosage-sensitive sex reversal.
Mouse sex determination genes  Links: The high mobility group HMG domain is a 79 amino acid protein region. For example, the platypus relies on an XY sex-determination system based on five pairs of chromosomes.
For related phenomena, see Androgen insensitivity syndrome and Intersex.
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Origins and evolution[ edit ] Before Y chromosome[ edit ] Many ectothermic vertebrates have no sex chromosomes. If they cromosoma y different sexes, sex is determined environmentally rather than genetically.
For some of them, especially reptilessex depends on the incubation temperature; others are hermaphroditic meaning they contain both male and female gametes in the same individual. Origin[ edit ] The X and Y chromosomes are thought to cromosoma y evolved from a pair of identical chromosomes,   termed autosomeswhen an ancestral animal developed an allelic variation, a so-called "sex locus" — simply possessing this allele caused the organism to be male.
Over time, genes that were beneficial for males and harmful to or had no effect on females either developed on the Y chromosome or were acquired through the process of translocation.
As a result, genes beneficial to males accumulated near the sex-determining genes, and recombination in this region was suppressed in order to preserve this male specific region.
Only cromosoma y tips of the Y and X chromosomes recombine. The tips of the Y chromosome that could recombine with the X chromosome are referred to as the pseudoautosomal region.
The cromosoma y of the Y chromosome is passed on to the next generation intact. It is because of this disregard for the rules cromosoma y the Y chromosome is such a superb tool for investigating recent human evolution.
Degeneration[ edit ] By one estimate, the human Y chromosome has lost 1, of its 1, original genes over the course of its existence, and linear extrapolation of this 1,gene loss over million years gives a rate of genetic loss of 4.
Degeneration may simply be the fate of all cromosoma y sex chromosomes, due to three common evolutionary forces: High mutation rate[ edit ] The human Y chromosome is particularly exposed to high mutation rates due to the environment in which it is housed.
The Y chromosome is passed exclusively through spermwhich undergo multiple cell divisions during gametogenesis.
Each cellular division provides further opportunity to accumulate base pair mutations.
Additionally, sperm are stored in the highly oxidative environment of the testis, which encourages further mutation. These two conditions cromosoma y put the Y chromosome at a greater risk of mutation than the rest of the genome.