Meiosis

11/13/14

Independent Assortment

The random assortment of homologous chromosomes that occurs during meiosis.


In independent assortment, trait alleles are seperated after the gamete is formed. After this occurs, the alleles are randomly united during fertilization.

Fertilization

The joining of egg and sperm (both haploid) to produce a diploid zygote.


Fertilization is commonly known as the union of male sperm and female egg or ovum. It is a sexual reproduction method in plants is known as pollination

Crossing Over

The exchange of genetic material that occurs between homologous chromosomes during the beginning of meiosis.


When crossing over happens in meiosis, two chromosomes pair up and exchange their genetic material. It is necessary for a variety in genes.

Mutations

A change in the order of nitrogen bases in a cell’s DNA that results in different genetic sequences.


Mutation occurs during deletion, addition, or exchanging of the genetic sequence. The mutation may create a new and original gene.

Nondisjunction

An alteration in which homologous chromosomes fail to separate normally during meiosis.


Nondisjunction is the failure of sister chromatids to separate during nuclear division. The daughter cells could also have abnormal amounts of chromosomes.