Meiosis Is Different From The Process Shown Because, During... ~ About News

Meiosis is divided into Meiosis I and Meiosis II because the initial cell divides twice producing four genetically different sex cells (gametes) Each time a cell divides, it goes through Prophase, Metaphase, Anaphase, and Telophase. See the link below for a diagram showing the process.Meiosis. Legend: Illustration of the process by which a single parent diploid cell (Both homologous chromosomes) divides to produce four daughter Meiosis is the type of cell division by which germ cells (eggs and sperm) are produced. Meiosis involves a reduction in the amount of genetic material.The process of meiosis happens in the male and female reproductive organs. Just like in mitosis, a cell All gametes are genetically different from each other. Comparing meiosis and mitosis. Two parents are needed in sexual reproduction. During this process the nuclei of the male and female...Mitosis Meiosis Mendelian Genetics. Quiz: Mitosis (Advanced). 1. The process of mitosis ensures that: each new cell is genetically different from its parent each new cell receives the proper number of chromosomes cells will divide at the appropriate time DNA is replicated without errors.Meiosis is the process in eukaryotic, sexually-reproducing animals that reduces the number of Meiosis is necessary for many sexually-reproducing animals to ensure the same number of In the first division, which consists of different phases, the duplicated DNA is separated into daughter cells.

Meiosis

Describe cellular events during meiosis. Explain the differences between meiosis and mitosis. Explain the mechanisms within meiosis that generate genetic Meiosis is preceded by an interphase consisting of the G 1 , S, and G 2 phases, which are nearly identical to the phases preceding mitosis.Mitosis vs meiosis - This lecture explains about the difference between Mitosis and meiosis cell division.Meiosis is a special kind of cell division that produces gametes (sperm and egg). Prior to the initiation of this process, the genetic materials is in the Genetic variability depends on the different alignment of the chromosome pairs during the meiosis I division. The two newly shuffled versions can place...Meiosis makes sperm and eggs. During meiosis in humans, 1 diploid cell (with 46 chromosomes or 23 pairs) undergoes 2 cycles of cell division but only 1 round of DNA replication. Independent assortment is the process where the chromosomes move randomly to separate poles during meiosis.

Sexual reproduction, meiosis and gamete formation - How do...

Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of Meiosis can be divided into nine stages. These are divided between the first time the cell divides Illustration showing the nine stages of meiosis. Image credit: Genome Research Limited.Meiosis is the process by which the number of chromosomes is halved during the formation of gametes. Only one function of meiosis is sexual division. With meiosis, children are slightly different from their parents because daughter cells are the connection of two parent cells (one egg...Definition of Meiosis. The word meiosis originated from the Greek word meioo, which means "to diminish," or "to make smaller." In literature, however, meiosis describes the use of understatement to highlight a point, or explain a situation, or to understate a response used to enhance the effect of a...Meiosis is the process by which most eukaryotic organisms, those with cells having an organized nucleus, produces sex cells, the male and female gametes. Meiosis occurs over two generations of cells. During normal cell division, or mitosis, each chromosome is copied, resulting in chromosomes...How meiosis reduces chromosome number by half: crossing over, meiosis I, meiosis II, and genetic variation. Biology is brought to you with support from the Amgen Foundation.

Learning Objectives

By the end of this phase, you will be able to:

Describe the conduct of chromosomes during meiosis Describe cell occasions during meiosis Explain the variations between meiosis and mitosis Explain the mechanisms inside of meiosis that generate genetic variation amongst the products of meiosis

Sexual reproduction requires fertilization, the union of two cells from two individual organisms. If the ones two cells each include one set of chromosomes, then the ensuing cell contains two units of chromosomes. Haploid cells contain one set of chromosomes. Cells containing two sets of chromosomes are known as diploid. The choice of sets of chromosomes in a cell is referred to as its ploidy level. If the reproductive cycle is to proceed, then the diploid cellular should one way or the other reduce its collection of chromosome sets earlier than fertilization can occur again, or there will probably be a continual doubling in the selection of chromosome units in each technology. So, in addition to fertilization, sexual replica features a nuclear division that reduces the selection of chromosome units.

Most animals and vegetation are diploid, containing two sets of chromosomes. In each somatic cellular of the organism (all cells of a multicellular organism aside from the gametes or reproductive cells), the nucleus contains two copies of each and every chromosome, known as homologous chromosomes. Somatic cells are every now and then known as "body" cells. Homologous chromosomes are matched pairs containing the similar genes in identical locations along their period. Diploid organisms inherit one copy of each homologous chromosome from every mother or father; all together, they're thought to be a complete set of chromosomes. Haploid cells, containing a single replica of each and every homologous chromosome, are found handiest inside of constructions that give rise to both gametes or spores. Spores are haploid cells that may produce a haploid organism or can fuse with another spore to form a diploid cellular. All animals and most vegetation produce eggs and sperm, or gametes. Some plants and all fungi produce spores.

The nuclear division that forms haploid cells, which is known as meiosis, is related to mitosis. As you may have realized, mitosis is the a part of a cellular copy cycle that leads to equivalent daughter nuclei which might be also genetically just like the authentic parent nucleus. In mitosis, each the guardian and the daughter nuclei are at the identical ploidy degree—diploid for many crops and animals. Meiosis employs a lot of the same mechanisms as mitosis. However, the beginning nucleus is all the time diploid and the nuclei that end result at the finish of a meiotic cellular division are haploid. To accomplish that aid in chromosome number, meiosis is composed of 1 round of chromosome duplication and two rounds of nuclear department. Because the events that occur during each of the division levels are analogous to the events of mitosis, the same level names are assigned. However, because there are two rounds of division, the major process and the phases are designated with a "I" or a "II." Thus, meiosis I is the first spherical of meiotic division and consists of prophase I, prometaphase I, and so on. Meiosis II, wherein the 2d round of meiotic department takes place, includes prophase II, prometaphase II, and so on.

Meiosis is preceded by way of an interphase consisting of the G1, S, and G2 phases, which are nearly just like the phases preceding mitosis. The G1 part, which is also referred to as the first gap phase, is the first part of the interphase and is excited about mobile expansion. The S part is the 2d section of interphase, during which the DNA of the chromosomes is replicated. Finally, the G2 phase, also referred to as the 2d gap section, is the 3rd and ultimate section of interphase; on this part, the cellular undergoes the final preparations for meiosis.

During DNA duplication in the S part, each chromosome is replicated to produce two an identical copies, known as sister chromatids, which might be held in combination at the centromere by way of cohesin proteins. Cohesin holds the chromatids in combination until anaphase II. The centrosomes, that are the buildings that arrange the microtubules of the meiotic spindle, also reflect. This prepares the mobile to go into prophase I, the first meiotic phase.

Prophase I

Figure 1. Early in prophase I, homologous chromosomes come together to shape a synapse. The chromosomes are sure tightly in combination and in easiest alignment by means of a protein lattice known as a synaptonemal complicated and by way of cohesin proteins at the centromere.

Early in prophase I, earlier than the chromosomes will also be noticed obviously microscopically, the homologous chromosomes are attached at their tips to the nuclear envelope by proteins. As the nuclear envelope starts to wreck down, the proteins related to homologous chromosomes convey the pair shut to one another. Recall that, in mitosis, homologous chromosomes don't pair in combination. In mitosis, homologous chromosomes line up end-to-end so that once they divide, each daughter cell receives a sister chromatid from each individuals of the homologous pair. The synaptonemal complex, a lattice of proteins between the homologous chromosomes, first bureaucracy at particular places after which spreads to cover the entire duration of the chromosomes. The tight pairing of the homologous chromosomes is referred to as synapsis. In synapsis, the genes on the chromatids of the homologous chromosomes are aligned exactly with each and every different. The synaptonemal advanced supports the exchange of chromosomal segments between non-sister homologous chromatids, a process called crossing over. Crossing over may also be observed visually after the alternate as chiasmata (singular = chiasma) (Figure 1).

In species reminiscent of humans, even if the X and Y intercourse chromosomes aren't homologous (most in their genes fluctuate), they have got a small region of homology that allows the X and Y chromosomes to pair up during prophase I. A partial synaptonemal complicated develops handiest between the areas of homology.

Figure 2. Crossover happens between non-sister chromatids of homologous chromosomes. The outcome is an alternate of genetic material between homologous chromosomes.

Located at intervals alongside the synaptonemal complicated are huge protein assemblies called recombination nodules. These assemblies mark the points of later chiasmata and mediate the multistep process of crossover—or genetic recombination—between the non-sister chromatids. Near the recombination nodule on each chromatid, the double-stranded DNA is cleaved, the cut ends are modified, and a new connection is made between the non-sister chromatids. As prophase I progresses, the synaptonemal complicated starts to wreck down and the chromosomes start to condense. When the synaptonemal complicated is long past, the homologous chromosomes remain connected to each other at the centromere and at chiasmata. The chiasmata remain till anaphase I. The selection of chiasmata varies in keeping with the species and the period of the chromosome. There must be no less than one chiasma in keeping with chromosome for proper separation of homologous chromosomes during meiosis I, however there may be as many as 25. Following crossover, the synaptonemal complex breaks down and the cohesin connection between homologous pairs is additionally got rid of. At the end of prophase I, the pairs are held together simplest at the chiasmata (Figure 2) and are known as tetrads because the 4 sister chromatids of every pair of homologous chromosomes are actually visual.

The crossover occasions are the first source of genetic variation in the nuclei produced by means of meiosis. A unmarried crossover event between homologous non-sister chromatids results in a reciprocal alternate of similar DNA between a maternal chromosome and a paternal chromosome. Now, when that sister chromatid is moved into a gamete cellular it'll lift some DNA from one mum or dad of the individual and a few DNA from the other parent. The sister recombinant chromatid has a combination of maternal and paternal genes that did not exist earlier than the crossover. Multiple crossovers in an arm of the chromosome have the identical impact, exchanging segments of DNA to create recombinant chromosomes.

Prometaphase I

The key match in prometaphase I is the attachment of the spindle fiber microtubules to the kinetochore proteins at the centromeres. Kinetochore proteins are multiprotein complexes that bind the centromeres of a chromosome to the microtubules of the mitotic spindle. Microtubules grow from centrosomes placed at reverse poles of the cellular. The microtubules transfer toward the middle of the cell and fix to considered one of the two fused homologous chromosomes. The microtubules connect at every chromosomes' kinetochores. With every member of the homologous pair attached to reverse poles of the cell, in the next section, the microtubules can pull the homologous pair apart. A spindle fiber that has attached to a kinetochore is known as a kinetochore microtubule. At the end of prometaphase I, each tetrad is connected to microtubules from each poles, with one homologous chromosome facing each and every pole. The homologous chromosomes are nonetheless held in combination at chiasmata. In addition, the nuclear membrane has broken down fully.

Metaphase I

During metaphase I, the homologous chromosomes are organized in the middle of the cell with the kinetochores dealing with reverse poles. The homologous pairs orient themselves randomly at the equator. For instance, if the two homologous individuals of chromosome 1 are categorised a and b, then the chromosomes may line up a-b, or b-a. This is essential in determining the genes carried by a gamete, as each will simplest receive considered one of the two homologous chromosomes. Recall that homologous chromosomes don't seem to be similar. They include slight variations of their genetic data, causing each and every gamete to have a unique genetic make-up.

This randomness is the bodily basis for the introduction of the 2nd type of genetic variation in offspring. Consider that the homologous chromosomes of a sexually reproducing organism are at the beginning inherited as two separate units, one from each and every dad or mum. Using humans as an example, one set of 23 chromosomes is found in the egg donated by means of the mother. The father provides the other set of 23 chromosomes in the sperm that fertilizes the egg. Every mobile of the multicellular offspring has copies of the original two sets of homologous chromosomes. In prophase I of meiosis, the homologous chromosomes shape the tetrads. In metaphase I, those pairs line up at the halfway point between the two poles of the mobile to form the metaphase plate. Because there is an equivalent chance that a microtubule fiber will encounter a maternally or paternally inherited chromosome, the association of the tetrads at the metaphase plate is random. Any maternally inherited chromosome would possibly face both pole. Any paternally inherited chromosome may additionally face either pole. The orientation of each tetrad is independent of the orientation of the different 22 tetrads.

This tournament—the random (or unbiased) collection of homologous chromosomes at the metaphase plate—is the second mechanism that introduces variation into the gametes or spores. In every cellular that undergoes meiosis, the association of the tetrads is different. The collection of diversifications is depending on the choice of chromosomes making up a collection. There are two possibilities for orientation at the metaphase plate; the imaginable choice of alignments subsequently equals 2n, the place n is the choice of chromosomes according to set. Humans have 23 chromosome pairs, which results in over eight million (223) possible genetically-distinct gametes. This number does now not include the variability that was up to now created in the sister chromatids via crossover. Given these two mechanisms, it is extremely unlikely that any two haploid cells ensuing from meiosis could have the identical genetic composition (Figure 3).

To summarize the genetic penalties of meiosis I, the maternal and paternal genes are recombined by way of crossover events that occur between each and every homologous pair during prophase I. In addition, the random assortment of tetrads on the metaphase plate produces a novel aggregate of maternal and paternal chromosomes that can make their way into the gametes.

Figure 3. Random, unbiased collection during metaphase I will be able to be demonstrated by means of making an allowance for a cell with a set of 2 chromosomes (n = 2). In this example, there are two conceivable arrangements at the equatorial aircraft in metaphase I. The overall conceivable collection of different gametes is 2n, where n equals the number of chromosomes in a collection. In this example, there are four possible genetic combinations for the gametes. With n = 23 in human cells, there are over Eight million conceivable combinations of paternal and maternal chromosomes.

Anaphase I

In anaphase I, the microtubules pull the related chromosomes aside. The sister chromatids stay tightly sure together at the centromere. The chiasmata are broken in anaphase I as the microtubules attached to the fused kinetochores pull the homologous chromosomes apart (Figure 4).

Telophase I and Cytokinesis

In telophase, the separated chromosomes arrive at reverse poles. The remainder of the standard telophase occasions might or may not occur, relying on the species. In some organisms, the chromosomes decondense and nuclear envelopes shape around the chromatids in telophase I. In other organisms, cytokinesis—the bodily separation of the cytoplasmic components into two daughter cells—happens without reformation of the nuclei. In nearly all species of animals and some fungi, cytokinesis separates the mobile contents by the use of a cleavage furrow (constriction of the actin ring that leads to cytoplasmic division). In vegetation, a cellular plate is shaped during cell cytokinesis by way of Golgi vesicles fusing at the metaphase plate. This mobile plate will in the long run result in the formation of mobile walls that separate the two daughter cells.

Two haploid cells are the finish results of the first meiotic department. The cells are haploid because at each pole, there is just one among every pair of the homologous chromosomes. Therefore, just one full set of the chromosomes is provide. This is why the cells are regarded as haploid—there is just one chromosome set, even supposing each and every homolog nonetheless consists of two sister chromatids. Recall that sister chromatids are simply duplicates of one in every of the two homologous chromosomes (with the exception of for changes that befell during crossing over). In meiosis II, these two sister chromatids will separate, developing four haploid daughter cells.

Link to Learning

Review the process of meiosis, watching how chromosomes align and migrate, at Meiosis: An Interactive Animation.

In some species, cells input a brief interphase, or interkinesis, ahead of entering meiosis II. Interkinesis lacks an S phase, so chromosomes aren't duplicated. The two cells produced in meiosis I'm going through the events of meiosis II in synchrony. During meiosis II, the sister chromatids inside of the two daughter cells separate, forming 4 new haploid gametes. The mechanics of meiosis II is similar to mitosis, excluding that each and every dividing cell has only one set of homologous chromosomes. Therefore, every mobile has part the selection of sister chromatids to separate out as a diploid cellular undergoing mitosis.

Prophase II

If the chromosomes decondensed in telophase I, they condense again. If nuclear envelopes were formed, they fragment into vesicles. The centrosomes that have been duplicated during interkinesis transfer away from each and every different towards reverse poles, and new spindles are formed.

Prometaphase II

The nuclear envelopes are utterly broken down, and the spindle is totally shaped. Each sister chromatid paperwork an individual kinetochore that attaches to microtubules from reverse poles.

Metaphase II

The sister chromatids are maximally condensed and aligned at the equator of the mobile.

Anaphase II

The sister chromatids are pulled apart through the kinetochore microtubules and move towards opposite poles. Non-kinetochore microtubules elongate the cell.

Figure 4. The process of chromosome alignment differs between meiosis I and meiosis II. In prometaphase I, microtubules connect to the fused kinetochores of homologous chromosomes, and the homologous chromosomes are organized at the midpoint of the cell in metaphase I. In anaphase I, the homologous chromosomes are separated. In prometaphase II, microtubules connect to the kinetochores of sister chromatids, and the sister chromatids are organized at the midpoint of the cells in metaphase II. In anaphase II, the sister chromatids are separated.

Telophase II and Cytokinesis

The chromosomes arrive at opposite poles and begin to decondense. Nuclear envelopes form round the chromosomes. Cytokinesis separates the two cells into four distinctive haploid cells. At this point, the newly shaped nuclei are both haploid. The cells produced are genetically unique as a result of the random collection of paternal and maternal homologs and as a result of the recombining of maternal and paternal segments of chromosomes (with their units of genes) that occurs during crossover. The complete process of meiosis is defined in Figure 5.

Figure 5. An animal mobile with a diploid selection of four (2n = 4) proceeds via the phases of meiosis to shape four haploid daughter cells.

Mitosis and meiosis are both forms of division of the nucleus in eukaryotic cells. They share some similarities, but also show off distinct differences that lead to very different results (Figure 6). Mitosis is a single nuclear division that ends up in two nuclei that are most often partitioned into two new cells. The nuclei resulting from a mitotic department are genetically identical to the original nucleus. They have the identical selection of sets of chromosomes, one set in the case of haploid cells and two sets in the case of diploid cells. In maximum plants and all animal species, it is in most cases diploid cells that undergo mitosis to form new diploid cells. In contrast, meiosis consists of 2 nuclear divisions leading to 4 nuclei which can be usually partitioned into 4 new cells. The nuclei resulting from meiosis are not genetically similar they usually comprise one chromosome set only. This is part the number of chromosome sets in the authentic mobile, which is diploid.

The main differences between mitosis and meiosis happen in meiosis I, which is a very different nuclear division than mitosis. In meiosis I, the homologous chromosome pairs grow to be associated with each different, are sure along side the synaptonemal complicated, broaden chiasmata and undergo crossover between sister chromatids, and line up along the metaphase plate in tetrads with kinetochore fibers from opposite spindle poles attached to each kinetochore of a homolog in a tetrad. All of these occasions happen only in meiosis I.

When the chiasmata unravel and the tetrad is broken up with the homologs moving to one pole or another, the ploidy degree—the choice of sets of chromosomes in each and every long term nucleus—has been lowered from two to one. For this explanation why, meiosis I is referred to as a discount division. There is no such relief in ploidy stage during mitosis.

Meiosis II is a lot more analogous to a mitotic department. In this case, the duplicated chromosomes (only one set of them) line up on the metaphase plate with divided kinetochores hooked up to kinetochore fibers from opposite poles. During anaphase II, as in mitotic anaphase, the kinetochores divide and one sister chromatid—now referred to as a chromosome—is pulled to at least one pole whilst the different sister chromatid is pulled to the different pole. If it weren't for the indisputable fact that there had been crossover, the two products of every individual meiosis II division would be similar (like in mitosis). Instead, they are different because there has at all times been no less than one crossover in step with chromosome. Meiosis II is not a discount division because despite the fact that there are fewer copies of the genome in the ensuing cells, there is nonetheless one set of chromosomes, as there used to be at the end of meiosis I.

Figure 6. Meiosis and mitosis are both preceded by way of one spherical of DNA replication; on the other hand, meiosis includes two nuclear divisions. The 4 daughter cells ensuing from meiosis are haploid and genetically distinct. The daughter cells ensuing from mitosis are diploid and similar to the guardian cell.

Evolution Connection The Mystery of the Evolution of Meiosis

Some characteristics of organisms are so popular and fundamental that it is infrequently tricky to remember that they developed like other simpler characteristics. Meiosis is such a very advanced sequence of mobile occasions that biologists have had hassle hypothesizing and trying out how it is going to have evolved. Although meiosis is inextricably entwined with sexual copy and its advantages and downsides, it is important to separate the questions of the evolution of meiosis and the evolution of sex, because early meiosis can have been positive for different causes than it is now. Thinking outside the field and imagining what the early benefits from meiosis might were is one approach to uncovering how it is going to have evolved.

Meiosis and mitosis percentage obtrusive cellular processes and it makes sense that meiosis advanced from mitosis. The issue lies in the transparent differences between meiosis I and mitosis.[1]

summarized the unique occasions that needed to happen for the evolution of meiosis from mitosis. These steps are homologous chromosome pairing, crossover exchanges, sister chromatids final connected during anaphase, and suppression of DNA replication in interphase. They argue that the first step is the hardest and maximum vital, and that working out the way it advanced would make the evolutionary process clearer. They counsel genetic experiments that may shed light on the evolution of synapsis.

There are different approaches to figuring out the evolution of meiosis in development. Different types of meiosis exist in single-celled protists. Some appear to be more effective or extra "primitive" kinds of meiosis. Comparing the meiotic divisions of different protists may make clear the evolution of meiosis.[2]

in comparison the genes inquisitive about meiosis in protists to grasp when and the place meiosis might have advanced. Although research is nonetheless ongoing, recent scholarship into meiosis in protists suggests that some aspects of meiosis could have developed later than others. This roughly genetic comparability can tell us what sides of meiosis are the oldest and what mobile processes they will have borrowed from in previous cells.

Link to Learning

Click via the steps of this interactive animation to check the meiotic process of mobile division to that of mitosis: How Cells Divide.

Section Summary

Sexual reproduction requires that diploid organisms produce haploid cells that may fuse during fertilization to form diploid offspring. As with mitosis, DNA replication occurs prior to meiosis during the S-phase of the cell cycle. Meiosis is a series of occasions that arrange and separate chromosomes and chromatids into daughter cells. During the interphases of meiosis, each chromosome is duplicated. In meiosis, there are two rounds of nuclear department leading to four nuclei and typically four daughter cells, every with half the number of chromosomes as the guardian cell. The first separates homologs, and the 2nd—like mitosis—separates chromatids into person chromosomes. During meiosis, variation in the daughter nuclei is introduced on account of crossover in prophase I and random alignment of tetrads at metaphase I. The cells that are produced via meiosis are genetically unique.

Meiosis and mitosis share similarities, but have distinct results. Mitotic divisions are single nuclear divisions that produce daughter nuclei that are genetically an identical and feature the similar choice of chromosome units as the original mobile. Meiotic divisions include two nuclear divisions that produce four daughter nuclei which can be genetically different and have one chromosome set instead of the two sets of chromosomes in the parent cellular. The major variations between the processes occur in the first department of meiosis, in which homologous chromosomes are paired and alternate non-sister chromatid segments. The homologous chromosomes separate into different nuclei during meiosis I, inflicting a discount of ploidy level in the first department. The 2nd department of meiosis is extra very similar to a mitotic department, except for that the daughter cells do not comprise equivalent genomes because of crossover.

Additional Self Check Questions

1. Describe the process that results i the formation of a tetrad.

2. Explain how the random alignment of homologous chromosomes during metaphase I contributes to the variation in gametes produced by meiosis.

3. What is the function of the fused kinetochore discovered on sister chromatids in prometaphase I?

4. In a comparison of the stages of meiosis to the stages of mitosis, which levels are distinctive to meiosis and which levels have the identical events in both meiosis and mitosis?

Answers 1. During the meiotic interphase, every chromosome is duplicated. The sister chromatids which might be shaped during synthesis are held in combination at the centromere region by means of cohesin proteins. All chromosomes are attached to the nuclear envelope through their pointers. As the mobile enters prophase I, the nuclear envelope starts to fragment, and the proteins maintaining homologous chromosomes locate each different. The 4 sister chromatids align lengthwise, and a protein lattice called the synaptonemal advanced is shaped between them to bind them together. The synaptonemal complicated facilitates crossover between non-sister chromatids, which is observed as chiasmata alongside the period of the chromosome. As prophase I progresses, the synaptonemal complex breaks down and the sister chromatids become loose, except for where they are attached by way of chiasmata. At this stage, the four chromatids are visual in every homologous pairing and are referred to as a tetrad. 2. Random alignment ends up in new mixtures of traits. The chromosomes that were initially inherited via the gamete-producing individual came similarly from the egg and the sperm. In metaphase I, the duplicated copies of these maternal and paternal homologous chromosomes line up across the center of the cellular. The orientation of every tetrad is random. There is an equal likelihood that the maternally derived chromosomes can be facing either pole. The similar is true of the paternally derived chromosomes. The alignment should occur in a different way in almost every meiosis. As the homologous chromosomes are pulled aside in anaphase I, any combination of maternal and paternal chromosomes will move towards every pole. The gametes shaped from those two groups of chromosomes will have a mix of characteristics from the particular person's folks. Each gamete is distinctive. 3. In metaphase I, the homologous chromosomes line up at the metaphase plate. In anaphase I, the homologous chromosomes are pulled aside and transfer to reverse poles. Sister chromatids are not separated till meiosis II. The fused kinetochore formed during meiosis I guarantees that every spindle microtubule that binds to the tetrad will attach to each sister chromatids.

4. All of the stages of meiosis I, aside from most likely telophase I, are unique as a result of homologous chromosomes are separated, now not sister chromatids. In some species, the chromosomes do not decondense and the nuclear envelopes don't shape in telophase I. All of the stages of meiosis II have the similar occasions as the phases of mitosis, with the conceivable exception of prophase II. In some species, the chromosomes are nonetheless condensed and there is no nuclear envelope. Other than this, all processes are the identical.