Answer:
Failure of chromosome to separate
Explanation:
The main essence of meiotic division is to form daughter cells with a reduced number of chromosomes that will maintain the correct chromosomal number in an organism. This is achieved when chromosomes separate during gamete formation (meiosis) to produce haploid (n) gametes.
However, a case may arise whereby chromosomes fail to separate during the anaphase stage of meiosis. This case is referred to as MEIOTIC NON-DISJUNCTION. As meiosis occurs in two stages i.e. meiosis I and II, so does meiotic nondisjunction. It can occur in meiosis I, where homologous chromosomes fail to separate or meiosis II, where sister chromatids fail to separate.
If it occurs in meiosis I, Two gametes will have a n-1 chromosome number i.e. one chromosome is missing while Two other gametes will have n+1 chromosome number i.e. one extra chromosome is added.
If it occurs in meiosis II, two normal haploid gametes (n) will be produced while the other two will have a n+1 and n-1 chromosome number respectively.
When these abnormal gametes (n+1, n-1) fuses with a normal gamete (n), the resulting organisms possess a chromosomal anomaly called ANEUPLOIDY i.e. a disorder in chromosomal number. The organisms will have 47 and 45 chromosomes depending on whether n+1 or n-1 gametes is involved respectively.
False
their legs were made form the spine of stingrays and they were used to ward of bad storms.
22 ) organelles are the tiny structures that carry out life activities !
23)mitosis as in this no variation takes place !
24) dominant trait.
and I am sure for all the three and suggest you to go for that !!!
By using microarray technology you can calculate the ratio by analyzing the colors on the glass plate. If the ratio is greater than 1, then the gene is induced by tumor formation. Less than 1 then it is suppressed by tumor formation. If the ratio is 0, the gene is not expressed in either cell. If the ratio is =<span> to 1, the gene is not affected.</span>
All of the above. Each cell is working and helping in different specialized ways in the body.
