What happens if nondisjunction occurs during meiosis?
If nondisjunction occurs in meiosis I, all four products of meiosis will be chromosomally abnormal. Two of the four products of meiosis will have two copies of the chromosome involved in the nondisjunction event, and two of the four products of meiosis will have no copies of that particular chromosome.
Which of the following is a result of nondisjunction?
Nondisjunction causes errors in chromosome number, such as trisomy 21 (Down syndrome) and monosomy X (Turner syndrome). It is also a common cause of early spontaneous abortions.
What is the outcome of nondisjunction in meiosis I quizlet?
There are three forms of nondisjunction: failure of a pair of homologous chromosomes to separate in meiosis I, failure of sister chromatids to separate during meiosis II, and failure of sister chromatids to separate during mitosis. Nondisjunction results in daughter cells with abnormal chromosome numbers (aneuploidy).
Which of the following happens if nondisjunction occurs during meiosis 2?
What happens if nondisjunction occurs during meiosis II? If nondisjunction occurs during meiosis II, sister chromatids fail to separate. In this case, 50% of the gametes that are produced are normal haploid gametes, 25% of gametes have an extra chromosome, and 25% are missing a chromosome.
What happens during meiosis to produce an aneuploid?
Aneuploidy is caused by nondisjunction, which occurs when pairs of homologous chromosomes or sister chromatids fail to separate during meiosis. The loss of a single chromosome from a diploid genome is called monosomy (2n-1), while the gain of one chromosome is called trisomy (2n+1).
Which describes the cells at the end of meiosis I when nondisjunction occurs during meiosis II?
One cell with extra homologous chromosomes and one cell missing a homologous chromosome. Which describes the cells at the end of meiosis I when nondisjunction occurs in meiosis II? The homologous pairs are in separate cells. The cells are haploid.
What happens in meiosis I?
In meiosis I, chromosomes in a diploid cell resegregate, producing four haploid daughter cells. It is this step in meiosis that generates genetic diversity. DNA replication precedes the start of meiosis I. During prophase I, homologous chromosomes pair and form synapses, a step unique to meiosis.
Which of the following processes occurs during meiosis but not mitosis?
The daughter cells produced by mitosis are identical, whereas the daughter cells produced by meiosis are different because crossing over has occurred. The events that occur in meiosis but not mitosis include homologous chromosomes pairing up, crossing over, and lining up along the metaphase plate in tetrads.