Cromosoma homólogo: Diferenzas entre revisións

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Miguelferig (conversa | contribucións)
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Liña 8:
Os cromosomas homólogos son normalmente similares en lonxitude, excepto nos cromosomas sexuais de moitos seres vivos, nos que o [[cromosoma X]] é considerablemente meirande ca o [[cromosoma Y|Y]]. Os cromosomas sexuais son teñen unha pequena rexión homóloga (ver [[rexión pseudoautosómica]]).
 
Os humanos temos 22 pares de homólogos de cromosomas non sexuais ou [[autosoma]]s, e un par de [[cromosoma sexual|cromosomas sexuais]]. Como as mulleres teñen dous cromosomas X, nelas o par sexual tamén é homólogo, pero como os homes teñen un cromosoma X e outro Y, estes só son parcialmente homólogos nunha pequena rexión.
Humans have 22 pairs of homologous non-sex chromosomes (called [[autosomes]]), and one pair of [[sex chromosome]]s, making a total of 46 chromosomes in a genetically normal human. Each member of a pair is inherited from one of the two parents. In addition to the 22 pairs of homologous autosomes, female humans have a homologous pair of sex chromosomes ([[X chromosome|two Xs]]), while males have an [[X chromosome|X]] and a [[Y chromosome]].
 
==Ploidía==
A [[ploidía]] dun organismo é o número de copias homólogas que ten de cada cromosoma. O número de cromosomas distintos (non homólogos) do organismo é o número monoploide (non é exactamente o mesmo ca o número haploide).
The [[ploidy]] of an organism is the number of homologous versions it has of each chromosome. If the chromosomes of an organism were separated into sets of completely non-homolougous chromosomes, the ploidy would be the number of such sets (and the number of chromosomes that would be in each such set is termed the monoploid number).
 
A maioría das plantas e animais son organismos [[diploide]]s. Os seus cromosomas aparecen en pares, xa que cada cromosoma ten un homólogo, pero están separados no núcleo da célula e só se xuntan na profase I da [[meiose]]. Cando na meiose se forman os gametos o número de cromosomas redúcese á metade e os gametos serán [[haploide]]s, xa que todos os seus cromosomas son distintos e non hai pares de homólogos.
Most plants and animals are [[diploid]] organisms. Their chromosomes come in pairs; each chromosome in a diploid organism has exactly one homologous partner. Each chromosome from these pairs is [[biological inheritance|inherited]] from a different [[parent]] (presuming the organism reproduces sexually from two parents). In fact the chromosomes physically arrange themselves into homologous pairs during [[meiosis]], and divide into monoploid (i.e., haploid) sets when forming [[gametes]].
 
Os organismos [[poliploide]]s teñen máis de dous cromosomas homólogos de cada. Por exemplo, un tetraploide terá catro de cada.
[[Polyploid]] organisms have more than two homologous chromosomes.
 
==Cromátidas irmás==
 
In meiosis [[sister chromatid]]s are each strand of the conjoined chromosomes which result from the replication and crossover of homologous chromosomes during that process, prior to separation during each of the two anaphases. This causes each of the four resultant gametes to have a unique genetic combination from both parents, providing the genetic variation upon which [[natural selection]] (the driver of the process of [[evolution]]) depends.
 
(Sister chromatids in mitosis are each strand of the two identical conjoined chromosomes (the product of chromosome replication) prior to separation during the [[anaphase]].)
 
==Notas==
Liña 28 ⟶ 22:
==Véxase tamén==
===Outros artigos===
*[[SynteniaSintenia]]
*[[Cigosidade]]