polyploidy in mammals?
107446
I am not sure.\nIf one X chromosome is de-activated normally perhaps the extra X chromosome in a polyploid individual is not.\nThe following link does not always open (!!!) - don't know why not. Also note it is PDF format.
504096
Presumably you don't mean monosomy X? Monosomy 10 seems to be something associated with some types of tumor cells not with a genetic disorder at birth
202968
If the rest of your question was: "What is the diploid number of chromosomes after synthesis?" Than the answer is still 12 because a haploid cell won't form until mitosis. If you clarify your question, you can get better answers. I'll come back to check.
950420
half a chromosome, a chromatid.
907218
Meiosis reduces a cell from a diploid cell to a haploid cell. This is important because if it didn't reduce a diploid to a haploid cell, when fertilization would occur, chromosomes would double and that is bad. Chromosome number is species based.\n\nSexual reproduction requires meiosis.\n\nMeiosis in stages....\n\nMeiosis1\n\nInterphase-same as interphase usually is. \n\nMeiosis I\nProphase I-crossing over (homologous chromosomes switch nonsister chromatids). Also the mitotic spindle fibers start forming from the aster and the nuclear envelope disappears.\n\nMetaphase I-The chromosomes meet together at the metaphasic plate, longest phase outside of interphase.\n\nAnaphase I-the chromosomes stay together (aka no break at centromere) they just don't pair up anymore. The pairs split, one chromosome going one way, the other going the other way.\n\nTelophase I and Cytokinesis-Nuclear envelope may or may not reform once the cleavage furrow or cell plate occur. Understand cytoplasmic inheritance with this as well.\n\nMeiosis II\n\nProphase (No interphase) II-no duplicaiton of chromosomes. The mitotic spindles form again\n\nMetaphase II-Everything goes towards the mitotic plate\n\nAnaphase II-The kinetochore spindles, or mitotic spindles, attach to the kinetochores and separate the chromosomes, bringing one chromatid to one end of the cell, another to the other end of the cell.\n\nTelophase II and cytokinesis-four haploid daughter cells are created. Think about it, meiosis I produces two cells, second division creates 4 because each diploid cell produces two haploids.
1018240
none\n\n\nyou start with one pair of homologous chromosomes in prophase I of meiosis I.  at metaphase I, these homologues line up across the metaphase plate, and at anaphase, they seperate so that one homologue goes to one pole, and the other homologue goes to the other pole.  after cytokinesis at the end of telophase I, you have one homologue in each cell...that homologue then goes through meiosis II, and at metaphase II, that homologue lines up at the metaphase plate with each sister chromatid facing each pole, and the chromosome is "pulled apart".  Anaphase II pulls the sister chromatids to each pole, and cytokinesis splits the one cell into two....two cells, each containing one sister chromatid of a homologous pair. (although in some text books this is refered to as a single homologue)
977774
each diploid organism receives two sets of chromosmes (one from the mother and one from father). during the reproduction of gamete cells, they go through meiosis which results in haploid cells (or cells with only half the number of a full set that a diploid organism would have). During fertilization, the two cells (egg and sperm) combine to give you a full set. (ex. your mother's egg and father's sperm each contain 23 chromosomes and came together to form a normal human with 46 chromosomes) That is why sex cells are always haploid.\n\nMathematically, if you think about it, its always something times 2 (in the previous example 23 * 2) thus the answer will always be even and a diploid organism will always have an even number of chromosomes
262929
Triploid fish are fish that have three sets of chromosomes in their cells, instead of the usual two (diploid) set most animals have.\n\nTriploid fish are usually sterile (the extra chromosomes really mess up the generation of sperm or eggs).  Because they are sterile, they have been used in some fish farms to reduce the danger to the environment if the fish escape.\n\nHowever, the triploid fish tend to be less resistant to disease and often have physical abnormalities that reduce their ability to thrive (they tend to be a tad gibbled in other words).
268425
Mendel's law of independent assortment basically says that each chromosome pair will separate during meiosis individually, regardless of whether the chromosome originated maternally or paternally.  So for example, if there are two pairs of chromosomes, 1 and 2, and each have a maternal and paternal copy (1M, 1P, 2M, and 2P), pairs 1 and 2 will segregate without input from the other pair.  So during meiosis, when the a haploid cell is formed with only one chromosome copy, there are many different combinations that can be formed.  The cell could contain 1M/2M, 1M/2P, 1P/2M, or 1P/2P.  It is easy to see how organisms with more chromosome pairs (humans have 23 pairs, 46 total) will produce more combinations, hence diversity among the species.  Hope that helps!
366636
there are some efforts going on to bring mammoth to life by using its frozen sperm. with an african elephant. as far as cloning goes i dont have any idea.
825948
Penguin says >>\n\nOogenesis is the process of females creating egg cells... When women are born, they have a lot of cells that of those egg cells, only a few will undergo meiosis and form egg cells. Meiosis, yes, does form four haploid cells from each one of those "pre-made egg cells". All those four haploid cells has 23 chromosomes. However, Meiosis only ensures that there are enough chromosomes for the offspring, and not necessarily the quality of the egg cell... \n\nWhat I mean is >> The larger egg cell containing more cytoplasm lives, while the other doesn't develope into an ovum. \n\nIn Meiosis I, the original cell divides into two, with 46 chromosomes. Meiosis does not seperate into two equal cells, as they do in mitosis. The larger cell then splits again [Meiosis II], and of the two haploid cells that result from Meiosis II, the larger one lives again. So, only one gamete is formed, though of the 4 haploids, 3 of the haploids degenerate. \n\n-- Cytokinesis isn't part of mitosis...Mitosis is part of the cell cycle, which has 3 steps :: interphase, mitosis, and cytokinesis. \n\nRemember that mitosis is the process of splitting a cell's nucleus. \n\nand remember that cytokinesis only splits two cells in half by pinching the cell membrane...\n\nSo... there's a difference. \n\nThank -you-\n\n<< Penguin waves good bye.
1052261
You are quite correct. This isn't a ground breaking observation or anything, although you did well to think of it on your own.\n\nThis is one of the major problems with hybrid animals and plants because the F1 generation is usually relatively uniform while the F2 generation can produce throwbacks to either or both grandparents. \n\nBecause the chromosomes are randomly assorted it is quite possible to produce an individual that contains little or even no genetic material from one or even two grandparents.
351459
I know you're probably needing a more direct answer, but there are _loads_ of information on polyandrous animals. Try using Google Scholar for serious scientific papers:\nhttp://scholar.google.com/scholar?hl=en&lr=&q=polyandry+evolution
719520
the ploidy no is 2n\nbut the dna amount is double. it changes in the metaphase or late prophase
626233
Mitosis allows the chromosomes in a cell to be duplicated so that a new cell can be formed. \nMeiosis uses the same concept except that you end up with four haploid( half the # of chromosomes) gametes, or reproductive cells because of the second half of the meiosis cycle. When these cells(either egg-sperm, pollen-seed, ect) come together, they form a diploid cell(twice the # of chromosomes as the haploid cell), which then has the number of chromosomes needed for the organism to grow and the species continue on. This also results in different combinations of genes, unlike mitosis, so there is some individuality amoung members of that species.
788673
that is not possible because of chromosomes that decide if we are boys or girls. Each animal has a certain number of cromosome in thier make up. Rabbits have different from dogs have different from cats etc. I dont know the exact number for bears but I promise you it is not 46 (if I remeber right) that humans have. these same chromosomes also determain your sex. guys are the x and girls are the y (i may have that backwards) hope this helps someone else may have more info but that is mostly the jist of it. Good luck.
46775
homologous chromosomes