Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Nondisjunction01:29

Nondisjunction

68.0K
During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
68.0K
Nondisjunction01:21

Nondisjunction

4.5K
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers.  Nondisjunction is common during anaphase I or anaphase II of meiosis.  Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold...
4.5K
Nondisjunction01:29

Nondisjunction

7.6K
7.6K
Genomic Imprinting and Inheritance02:30

Genomic Imprinting and Inheritance

30.2K
Diploid organisms inherit genetic material through chromosomes from both parents. Copies of the same gene are known as alleles. In most cases, both alleles are simultaneously expressed and allow various cellular processes to function optimally. If one of the alleles is missing or mutated, the expression of the other allele can compensate; however, this is not true for all genes.
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
30.2K
Meiosis I01:49

Meiosis I

176.7K
Meiosis is a carefully orchestrated set of cell divisions, the goal of which—in humans—is to produce haploid sperm or eggs, each containing half the number of chromosomes present in somatic cells elsewhere in the body. Meiosis I is the first such division, and involves several key steps, among them: condensation of replicated chromosomes in diploid cells; the pairing of homologous chromosomes and their exchange of information; and finally, the separation of homologous chromosomes by...
176.7K
Meiosis I03:09

Meiosis I

30.8K
Meiosis is the division of a diploid cell into haploid cells forming sperm and eggs in animals through differentiation. Meiosis I is the first stage of meiosis, where the genetic recombination of homologous chromosomes and the reduction of the ploidy level by half occurs.
Prophase I is the most extended and complex step of meiosis I characterized by synapsis, chromosome pairing, and recombination of the homologous chromosomes. This process is facilitated by a proteinaceous structure called the...
30.8K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

The effects of a novel combination of a probiotic supplement (L. rhamnosus GG, L. acidophilus, and L. casei) with a weight gain intervention on body composition, appetite, gut permeability, oxidative stress, and inflammation in underweight adults: study protocol for a double-blind, randomized controlled trial.

BMC nutrition·2026
Same author

From Plate to Patient: A Systematic Review of Food-Related Campylobacteriosis Case Reports.

Health science reports·2026
Same author

Montelukast impressively mitigates biomarkers of inflammation in non-ST-segment elevation myocardial infarction patients: a randomized, double-blind, placebo-controlled clinical trial.

Naunyn-Schmiedeberg's archives of pharmacology·2026
Same author

Decline in exclusive breastfeeding beyond early infancy, regional variations, socioeconomic influences, and growth outcomes: a population-based study from northeastern Iran.

International breastfeeding journal·2025
Same author

The Effectiveness of Herbal Mixture of Echium amoenum L. and Rheum ribes on Obsessive-Compulsive Disorder: A Randomized Controlled Triple-Blind Clinical Trial.

Neuropsychopharmacology reports·2025
Same author

Molecular characterization and phylogenetic analysis of cryptosporidium spp. in pediatric acute gastroenteritis: Epidemiological insights from northeastern Iran.

New microbes and new infections·2025

Related Experiment Video

Updated: May 3, 2026

Pre-Implantation Genetic Testing for Aneuploidy on a Semiconductor Based Next-Generation Sequencing Platform
09:30

Pre-Implantation Genetic Testing for Aneuploidy on a Semiconductor Based Next-Generation Sequencing Platform

Published on: August 17, 2022

2.1K

Down syndrome and consanguinity.

Amir Akhavan Rezayat1, Mohammad Hassanzadeh Nazarabadi2, Mohammad Sobhan Sheikh Andalibi1

  • 1Student Research Committee, Faculty of Medicine, Mashhad, Iran.

Journal of Research in Medical Sciences : the Official Journal of Isfahan University of Medical Sciences
|February 14, 2014
PubMed
Summary
This summary is machine-generated.

Down syndrome (DS) occurs more frequently in non-consanguineous marriages, with mothers of affected children in these unions being older. This suggests DS screening for all embryos may be beneficial.

Keywords:
ConsanguinityDown syndromechromosomal disorder

More Related Videos

Generation of Induced Pluripotent Stem Cells from Turner Syndrome 45XO Fetal Cells for Downstream Modelling of Neurological Deficits Associated with the Syndrome
09:39

Generation of Induced Pluripotent Stem Cells from Turner Syndrome 45XO Fetal Cells for Downstream Modelling of Neurological Deficits Associated with the Syndrome

Published on: December 4, 2021

2.5K
FISH for Pre-implantation Genetic Diagnosis
07:34

FISH for Pre-implantation Genetic Diagnosis

Published on: February 23, 2011

40.0K

Related Experiment Videos

Last Updated: May 3, 2026

Pre-Implantation Genetic Testing for Aneuploidy on a Semiconductor Based Next-Generation Sequencing Platform
09:30

Pre-Implantation Genetic Testing for Aneuploidy on a Semiconductor Based Next-Generation Sequencing Platform

Published on: August 17, 2022

2.1K
Generation of Induced Pluripotent Stem Cells from Turner Syndrome 45XO Fetal Cells for Downstream Modelling of Neurological Deficits Associated with the Syndrome
09:39

Generation of Induced Pluripotent Stem Cells from Turner Syndrome 45XO Fetal Cells for Downstream Modelling of Neurological Deficits Associated with the Syndrome

Published on: December 4, 2021

2.5K
FISH for Pre-implantation Genetic Diagnosis
07:34

FISH for Pre-implantation Genetic Diagnosis

Published on: February 23, 2011

40.0K

Area of Science:

  • Genetics
  • Medical Genetics
  • Human Genetics

Background:

  • Down syndrome (DS) is a leading genetic cause of intellectual disability, congenital heart defects, and intestinal issues.
  • Currently, no definitive treatments exist for Down syndrome.
  • Understanding epidemiological factors like parental consanguinity and maternal age is crucial for DS research.

Purpose of the Study:

  • To investigate the frequency of parental consanguinity in Down syndrome cases.
  • To analyze the relationship between maternal age and Down syndrome occurrence.
  • To explore potential correlations between marriage type and DS prevalence.

Main Methods:

  • Karyotyping using the G-banding method was performed on 38 confirmed Down syndrome patients.
  • Data on parental consanguinity and maternal age were collected and analyzed.
  • Patients were recruited from a referral University Hospital's genetics laboratory.

Main Results:

  • Free trisomy was the most prevalent chromosomal abnormality, accounting for 92.1% of cases.
  • Down syndrome was observed more frequently in non-consanguineous marriages (71.1%) than consanguineous ones (28.9%).
  • Maternal age was higher in non-consanguineous unions (mean 31.1 ± 7.7 years) compared to consanguineous unions (mean 27.1 ± 6.3 years).

Conclusions:

  • The higher incidence of DS in non-consanguineous marriages warrants further investigation.
  • Findings suggest that Down syndrome diagnostic testing could be considered for all embryos, irrespective of parental relationship.
  • This study highlights the importance of epidemiological factors in understanding Down syndrome prevalence.