What is the importance of "cross-over" during meiosis?

Answer 1

During cross-over segments of DNA are exchanged between the pairs of homologous chromosomes. Once they separate and gametes are formed, every daughter chromosome is different from the parental ones and carries a new combination of alleles. This is how genetic diversity is generated and is the basis of sexual reproduction. It is the genetic diversity between individuals that allows natural selection to operate and ultimately drives the adaptation of species to their environments.

Answer 2

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It unlinks alleles that are found on the same chromosome. It allows pairs of chromosomes to swap different copies of the same genes. This increases genetic variability, allowing for even more possible combinations of traits than you'd get just by randomly separating chromosomes during meiosis.

Answer 3

Increasing genetic variation, as without crossover the only variation that would occur would be due to independent assortment of the chromosomes during meiosis.

Answer 4

The crossing over is very important during meiosis because it is the one that guarantees the genetic variability, making us different.

Answer 5

'Cross over' is scientifically known as the process of chiasma. In Prophase I, homologous chromosomes form bivalents in a process called synapsis. When bivalents form, sections of the chromatids can break off and reciprocally swap portions of DNA.

Chiasma, independent assortment (metaphase I & II), random fusion of gametes and random mutation are all responsible for genetic variation within a species. Independent assortment is the most important since it enables each allele of a gene to end up in a gamete with the allele from another gene (thus you get four gametes of four different genotypes in a single monohybrid cross). Random fertilisation is responsible for allowing these different genotypes to occur in a population (genotype affects phenotype) and thus you get the various ratios in punnet squares.

Answer 6

Meiosis increases the probability of your germ line and species surviving into the indefinite future, stirring the gene pool and promoting variation upon which natural selection can work.

Answer 7

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Answer 8

in meiosis, four identical haploid cells are created. crossing over is when sections of chromatids from 2 different chromosomes exchange part of their chromatid with each other - ie adjacent chromatids overlap when tetrads form. the result is increased genetic variation in the resulting daughter cells.

see http://www.sumanasinc.com/webcontent/anisamples/majorsbiology/meiosis.html for animated explanation

Answer 9

the more variety that is seen in the daughter cells, the better the chnce is of survival. crossing over swaps some of the genes around that wouldnt normally be swapped for example if black hair and big feet were on the same chromosome, they would always been seen together, black haired kids with big feet but with crossing over you could then have black haired kids with small feet or blonde haired kids with big feet.

ok, so big feet may not matter to us but if its rabbits, then they want as many of their offspring to have the best features, and if a poor feature and a good feature are stuck on the same chromosome then they will always have average offspring which may not survive but thanks to crossing over, they can have excellent offspring with excellent features and offspring which will probably die because of their poor features but, at least most of their offspring will live thanks to their dominant excllent features.

Answer 10

Crossing over is important so that no 2 daughter cells have the same genetics.