Two pairs of homologous chromosomes line up and form a tetrad near the beginning of prophase I of meiosis. The tetrads then perform the crossing over and recombination process before migrating to the cell equator.
well it is form in a two pair image where they are side by side
Metaphase
Phophase I
prophase 1
Plato = B tetrad synapsis
Prophase I
During meiosis, genetic recombination of homologous chromosomes occurs. So meiosis does result in genetic variation. After prophase I, during which crossing over occurs, every chromosome will have some maternal DNA and some paternal DNA.
Crossing overIndependent assortmentRandom fertilizationMutation1. Crossing overCrossing over is the exchange of corresponding segments of non-sister chromatids of homologous chromosomes. During prophase I (of meisosis I), homologous chromosomes synapse to form aggregates called either bivalents (bi = 2, and there are two homologous chromosomes in the aggregate) or tetrads (tetra = 4, and there are 4 chromatids in the aggregate). While the chromosomes are synapsed in prophase I, crossing over occurs. As a result, a chromatid that originally consisted of 100% maternal alleles and a chromatid that originally consisted of 100% paternal alleles become chromatids with a mixture of both maternal and paternal alleles. This shuffles genetic information and increases variation.2. Independent assortmentIn metaphase I (of meiosis I), the tetrads (bivalents) line up at the center of the cell. Which pole the maternal and paternal chromosomes face is a matter of chance; and the direction the maternal and paternal chromosomes face in one tetrad has no bearing on which way the maternal and paternal chromosomes of another tetrad face. Thus, when the homologous chromosomes separate and move to opposite poles, each pole will receive a mix of maternal and paternal chromosomes. This shuffles genetic information and increases variation.3. Random fertilizationBecause of the above processes, male animals can potentially produce millions or hundreds of millions of genetically unique sperm. And, male animals typically release millions of sperm during sex. Which one of the millions of genetically unique sperm happens to end up fertilizing the egg is largely a matter of chance. Thus, except foridentical twins, siblings never have exactly the same genetic information.4 Mutation takes place during replication of DNA which result in new varieties .
Daughter cells usually have a mixture of maternal and paternal chromosomes during meiosis 1
The homologous pairs of chromosomes line up together forming tetrads. During this time, chromatids from the homologous chromosomes cross over and exchange segments so that each chromatid contains both maternal and paternal DNA.
Plato = B tetrad synapsis
Prophase I
independent assortment
During meiosis, genetic recombination of homologous chromosomes occurs. So meiosis does result in genetic variation. After prophase I, during which crossing over occurs, every chromosome will have some maternal DNA and some paternal DNA.
Crossing overIndependent assortmentRandom fertilizationMutation1. Crossing overCrossing over is the exchange of corresponding segments of non-sister chromatids of homologous chromosomes. During prophase I (of meisosis I), homologous chromosomes synapse to form aggregates called either bivalents (bi = 2, and there are two homologous chromosomes in the aggregate) or tetrads (tetra = 4, and there are 4 chromatids in the aggregate). While the chromosomes are synapsed in prophase I, crossing over occurs. As a result, a chromatid that originally consisted of 100% maternal alleles and a chromatid that originally consisted of 100% paternal alleles become chromatids with a mixture of both maternal and paternal alleles. This shuffles genetic information and increases variation.2. Independent assortmentIn metaphase I (of meiosis I), the tetrads (bivalents) line up at the center of the cell. Which pole the maternal and paternal chromosomes face is a matter of chance; and the direction the maternal and paternal chromosomes face in one tetrad has no bearing on which way the maternal and paternal chromosomes of another tetrad face. Thus, when the homologous chromosomes separate and move to opposite poles, each pole will receive a mix of maternal and paternal chromosomes. This shuffles genetic information and increases variation.3. Random fertilizationBecause of the above processes, male animals can potentially produce millions or hundreds of millions of genetically unique sperm. And, male animals typically release millions of sperm during sex. Which one of the millions of genetically unique sperm happens to end up fertilizing the egg is largely a matter of chance. Thus, except foridentical twins, siblings never have exactly the same genetic information.4 Mutation takes place during replication of DNA which result in new varieties .
Homologous chromosomes are a set of chromosome pairs, one set maternal and the other paternal, that pair up during meiosis, the production of reproductive cells. The pairs have the same genes in the same locations, though once spread out the different pairs segregate out. the biggest way that these chromosomes change up is by exchanging lengths of the material.
Daughter cells usually have a mixture of maternal and paternal chromosomes during meiosis 1
Swapping of genetic genetic material is when two chromosomes (maternal and paternal) with the same gene sequence exchange genes, this occurs during Phrophase 1 of meiosis by a process called crossing over. Hope this helps.
independent assortment :)
In Prophase I: - The duplicated chromatin condenses. Each chromosome consists of two, closely associated sister chromatids. - DNA is exchanged between homologous (similar) chromosomes in a process called 'homologous recombination'. - This often results in the non-sister chromatids crossing over*. The new combinations of DNA created during crossover are a significant source of genetic variation. *at points called chiasmata (plural; singular chiasma).
During meiosis, the homologous chromosomes come together during prophase I. Pairs of homologous chromosomes align during a process called synapsis and form a tetrad (four sister chromatids, two from each pair of homologous chromosomes). During synapsis, crossing over may occur, during which homologous chromosomes exchange genetic material.