Related Experiment Video

Updated: Aug 7, 2026

Chromosome Preparation From Cultured Cells
07:42

Chromosome Preparation From Cultured Cells

Published on: January 28, 2014

Assignment of the gene for cystathionine beta-synthase to human chromosome 21 in somatic cell hybrids

F Skovby, N Krassikoff, U Francke

    Human Genetics
    |January 1, 1984
    PubMed

    Insights

    The human gene for cystathionine beta-synthase (CBS) is located on chromosome 21. This finding is crucial for understanding homocystinuria, a genetic disorder.

    Area of Science:

    • Genetics
    • Biochemistry
    • Molecular Biology

    Background:

    • Cystathionine beta-synthase (CBS) deficiency causes homocystinuria.
    • Identifying the gene responsible for CBS is essential for genetic research and diagnostics.

    Purpose of the Study:

    • To determine the chromosomal location of the human gene encoding cystathionine beta-synthase (CBS).
    • To investigate the genetic basis of homocystinuria.

    Main Methods:

    • Screening of mouse, rat, and Chinese hamster cell lines for CBS activity.
    • Creation and analysis of somatic cell hybrids between human and Chinese hamster cells.
    • Segregation analysis of human chromosomes with CBS activity in hybrid cells.

    Main Results:

    • Mouse 3T3 and Chinese hamster Don fibroblasts showed no detectable CBS activity.
    • Somatic cell hybrids indicated that human chromosome 21 cosegregated with CBS activity.
    • Hybrids with mutant human fibroblasts confirmed chromosome 21 as the location for the CBS gene.

    Conclusions:

    • The human gene for CBS is located on chromosome 21.
    • This localization provides insight into the genetic cause of homocystinuria.

    More Related Videos

    In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila06:41

    In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila

    Published on: August 20, 2019

    Transmitochondrial Cybrid Generation Using Cancer Cell Lines07:49

    Transmitochondrial Cybrid Generation Using Cancer Cell Lines

    Published on: March 17, 2023

    Related Concept Videos

    Karyotyping01:17

    Karyotyping

    Describing the number and physical features of chromosomes can reveal abnormalities that underlie genetic diseases. This description is facilitated by special staining techniques that produce a particular banding pattern on each chromosome. State-of-the-art techniques make this approach even more powerful, enabling the detection of individual genes that cause disease.A Simple Chromosome Staining Technique Provides Valuable Scientific InsightSome genetic diseases can be detected by looking at...
    Mutations01:39

    Mutations

    Overview
    Inheritance of Chromatin Structures03:17

    Inheritance of Chromatin Structures

    Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the differential gene expression pattern to maintain cell lineage, position-effect variegation, dosage compensation, and maintenance of chromatin structures such as telomeres and centromeres. For example, the structure and location of the centromere on chromosomes are epigenetically inherited. Its functionality is not dictated or ensured by the underlying DNA...
    Gene Conversion02:08

    Gene Conversion

    Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...
    Genome Copying Errors02:46

    Genome Copying Errors

    DNA replication is a well-evolved process that copies millions of base pairs with high fidelity during each cell division. Occasionally a wrong base or a long stretch of wrong bases may get added to the daughter strands. If the errors are left unchecked, cells might accumulate several mutations that might endanger their  survival. Therefore, the copying errors are checked and repaired at three levels.
    Synteny and Evolution02:31

    Synteny and Evolution

    John H. Renwick first coined the term “synteny” in 1971, which refers to the genes present on the same chromosomes, even if they are not genetically linked. The species with common ancestry tend to show conserved syntenic regions. Therefore, the concept of synteny is nowadays used to describe the evolutionary relationship between species.
    Around 80 million years ago, the human and mice lineages diverged from the common ancestor. During the course of evolution, the ancestral chromosome underwent...