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Lecture

Chromosomes and Meiosis: Understanding Genetic Variation

In course

BIO-105: Cellular biology and biochemistry for engineers

Basic course in biochemistry as well as cellular and molecular biology for non-life science students enrolling at the Master or PhD thesis level from various engineering disciplines. It reviews essential notions necessary for a training in biology-related ...

Description

This lecture covers the process of chromosomes duplicating, homologous chromosomes separating, and sister chromatids separating in meiosis. It also explains the different stages of meiosis, including metaphase, prophase, and spindle microtubule formation, as well as the consequences of nondisjunction in meiosis. The lecture concludes with the impact of nondisjunction on fertilization, leading to genetic variation.

Instructor

Romain Zufferey

Official source

Ontological neighbourhood

Biology

Cell biology: Cell cycle

Molecular biology: Chromosomes

Related concepts (32)

Homologous chromosome

A couple of homologous chromosomes, or homologs, are a set of one maternal and one paternal chromosome that pair up with each other inside a cell during fertilization. Homologs have the same genes in the same loci where they provide points along each chromosome which enable a pair of chromosomes to align correctly with each other before separating during meiosis. This is the basis for Mendelian inheritance which characterizes inheritance patterns of genetic material from an organism to its offspring parent developmental cell at the given time and area.

Y chromosome

The Y chromosome is one of two sex chromosomes in therian mammals and other organisms. The other sex chromosome is the X chromosome. Y is normally the sex-determining chromosome in many species, since it is the presence or absence of Y that determines the male or female sex of offspring produced in sexual reproduction. In mammals, the Y chromosome contains the gene SRY, which triggers male development. The DNA in the human Y chromosome is composed of about 62 million base pairs, making it similar in size to chromosome 19.

Meiosis

Meiosis (maɪˈoʊsɪs; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately result in four cells with only one copy of each chromosome (haploid). Additionally, prior to the division, genetic material from the paternal and maternal copies of each chromosome is crossed over, creating new combinations of code on each chromosome.

Chromosome

A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation.

X chromosome

The X chromosome is one of the two sex chromosomes in many organisms, including mammals, and is found in both males and females. It is a part of the XY sex-determination system and XO sex-determination system. The X chromosome was named for its unique properties by early researchers, which resulted in the naming of its counterpart Y chromosome, for the next letter in the alphabet, following its subsequent discovery. It was first noted that the X chromosome was special in 1890 by Hermann Henking in Leipzig.

Related lectures (32)

Cellular Biology: Mitosis and Meiosis Overview

Covers cellular biology, focusing on mitosis, meiosis, and the cell cycle processes.

Meiosis: Gamete Formation and Chromosome Division

Explores meiosis, gamete formation, chromosome division, and consequences of nondisjunction.

Meiosis: Chromosome Division and Genetic Shuffling

Explores meiosis, focusing on chromosome division, genetic shuffling, and consequences of errors.

Mitosis and Cell Cycle

Explains the process of mitosis and the cell cycle phases.

DNA Replication: Sister Chromatids Cohesion