During anaphase I the chromosomes do NOT split into separate chromatids. During anaphase I, the sister chromatids remain connected, and each of the initial two daughter cells receives one of each homologous pair of the original chromosomes. Separation of the chromatids occurs during anaphase II, with each of the four resulting cells receiving one chromatid.
There are two phases of meiosis, ultimately resulting in four daughter cells (in the case of egg cells, only one of the four is functional).
Crossing over does indeed happen during prophase I, when the homologous chromosomes are so close to each other that they can exchange sections of genetic material with each other.
Homologous chromosomes form tetrads--this is when the two homologous chromosomes of each set pair up prior to being separated during the first phase of meiosis.
No comments:
Post a Comment