Answer to Question #175523 in Genetics for John

Question

Explain the terms Chromosome, Chromatid, Gene, Allele.

(Use genetic notation (symbols for alleles) and annotated diagrams to illustrate your response. Show links between the terms)

2. Using mainly labelled diagrams, (and some explanation) describe the sequence of events in the process of Meiosis in eukaryotic cells.

Indicate clearly where the opportunities arise in meiosis for genetic variation and outline and illustrate briefly how this happens.

Answer 1

A chromosome is a long DNA molecule with part or all of the genetic material of an organism. i.e X or Y

A chromatid is one of two identical halves of a replicated chromosome.

A gene is the basic physical and functional unit of heredity.

An allele is a variant form of a gene.

Meiosis can only occur in eukaryotic organisms. It is preceded by interphase, specifically the G phase of interphase. Both Meiosis I and II have the same number and arrangement of phases: prophase, metaphase, anaphase, and telophase. Both produce two daughter cells from each parent cell.