Related Experiment Video
Updated: Jun 23, 2026
06:18
Frequency and Distribution of Crossovers in Caenorhabditis elegans Meiosis by SNP Genotyping using Real-time PCR
Published on: July 11, 2025
Determining crossover count and position in two pig lines with different selection histories.
Olivia Katz1, Anne C M Jansen2, Tom Druet3
1Animal Breeding and Genomics, Wageningen University and Research, Wageningen, 6700 AH, The Netherlands. olivia.katz@wur.nl.
Genetics, Selection, Evolution : GSE
|June 20, 2026
Summary
Female pigs transmit more crossovers than males, potentially increasing genetic variation. Understanding these crossover patterns is key for livestock breeding programs aiming to enhance genetic diversity.
Area of Science:
- Genetics
- Animal Breeding
- Meiosis
Background:
- Crossovers are vital for genetic variation during meiosis.
- Their application in livestock breeding remains largely unexplored.
- This study investigates crossover patterns in pig breeding lines.
Purpose of the Study:
- To analyze autosomal crossover counts (ACC) in two pig lines with distinct selection histories.
- To compare intrachromosomal genetic shuffling and inter-crossover distances.
- To examine recombination landscapes in individuals with high versus low crossover counts.
Main Methods:
- Genomic data analysis of over 125,000 individuals from boar and sow lines.
- Utilized over 20,000 autosomal single nucleotide polymorphisms (SNPs).
- Estimated and compared ACC, genetic shuffling, and inter-crossover distances.
Main Results:
- Mean ACC was ~20 in both boar and sow lines.
- Dams transmitted more crossovers than sires.
- Sows exhibited slightly higher genetic shuffling; sires spaced crossovers more evenly, except on shortest chromosomes.
Conclusions:
- Confirms higher crossover transmission by dams.
- Crossover counts may differ between lines due to selection history.
- Crossover localization influences genetic variance, impacting breeding program strategies.
Related Concept Videos
01:34Crossing Over
Unlike mitosis, meiosis aims for genetic diversity in its creation of haploid gametes. Dividing germ cells first begin this process in prophase I, where each chromosome—replicated in S phase—is now composed of two sister chromatids (identical copies) joined centrally.
The homologous pairs of sister chromosomes—one from the maternal and one from the paternal genome—then begin to align alongside each other lengthwise, matching corresponding DNA positions in a process called synapsis.
In order to...
The homologous pairs of sister chromosomes—one from the maternal and one from the paternal genome—then begin to align alongside each other lengthwise, matching corresponding DNA positions in a process called synapsis.
In order to...
01:30Crossing Over
Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to allelic diversity in the newly formed daughter cells. In humans, crossing over produces genetically distinct haploid egg and sperm cells that undergo fertilization to produce unique offspring. Before cell division starts, the germ cell’s chromosome(s) undergo duplication in the S phase of the cell cycle. As the cells enter prophase I, duplicated...
02:27Trihybrid Crosses
Trihybrid Crosses
Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A trihybrid cross is a combination of three individual monohybrid crosses. For example, plant height (tall vs. short), seed shape (round vs. wrinkled), and seed color (yellow vs. green).
The F1 generation plants of a trihybrid cross are heterozygous for all three traits and produce eight gametes. Upon self-fertilization, these gametes have an equal chance to...
Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A trihybrid cross is a combination of three individual monohybrid crosses. For example, plant height (tall vs. short), seed shape (round vs. wrinkled), and seed color (yellow vs. green).
The F1 generation plants of a trihybrid cross are heterozygous for all three traits and produce eight gametes. Upon self-fertilization, these gametes have an equal chance to...
01:39Test Cross
Alleles are different forms of the same gene. Humans and other diploid organisms inherit two alleles of every gene, one from each parent.
01:39Test Cross
Alleles are different forms of the same gene. Humans and other diploid organisms inherit two alleles of every gene, one from each parent.
01:16Crossover Experiments
Crossover experiments, also called the repeated-measurements design, is a study design in which all experimental units are exposed to all treatments in different periods. Crossover experiments are generally used in psychology, the pharmaceutical industry, agriculture, and medicine.
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.