Related Experiment Video
Updated: Jun 24, 2026
07:54
Manipulation of Ploidy in Caenorhabditis elegans
Published on: March 15, 2018
Summary
Hermaphroditism was observed in Meloidogyne hapla, a plant-parasitic nematode. This condition, where females produce sperm but do not use it for reproduction, occurred in approximately 50% of progeny, with inheritance patterns suggesting cytoplasmic factors.
Area of Science:
- Nematology
- Developmental Biology
- Genetics
Background:
- Meloidogyne hapla, a significant plant-parasitic nematode, exhibits complex reproductive strategies.
- Understanding reproductive anomalies like hermaphroditism is crucial for nematode management and evolutionary studies.
Purpose of the Study:
- To investigate the occurrence and characteristics of hermaphroditism in Meloidogyne hapla isolates.
- To explore the inheritance patterns and potential influencing factors of hermaphroditism in this nematode species.
Main Methods:
- Observation of hermaphrodites in diploid and polyploid Meloidogyne hapla isolates (population 86-Va).
- Analysis of gonad development and spermatogenesis timing in hermaphroditic individuals.
- Controlled crosses and temperature regime experiments to assess inheritance and environmental influences.
Main Results:
- Hermaphroditism was detected, characterized by the development of functional sperm in otherwise female nematodes.
- Hermaphroditic individuals produced approximately 50% hermaphroditic progeny, with normal-appearing females also producing hermaphroditic offspring.
- Temperature variations did not affect the percentage of hermaphrodites; crosses suggested non-nuclear inheritance, though not definitively proven.
Conclusions:
- Hermaphroditism in Meloidogyne hapla is a non-functional trait where produced sperm is not utilized for reproduction.
- The inheritance of hermaphroditism appears to be influenced by non-nuclear factors, warranting further investigation.
- This phenomenon has implications for understanding nematode population dynamics and reproductive biology.
Related Concept Videos
02:45The Ratio of X Chromosome to Autosomes
In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
02:50Dosage Compensation
In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one Y chromosome, whereas C.elegans with one X chromosome is a male, and the one with two X chromosomes is a hermaphrodite.
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
01:43Incomplete Dominance
Gregor Mendel's work (1822 - 1884) was primarily focused on pea plants. Through his initial experiments, he determined that every gene in a diploid cell has two variants called alleles inherited from each parent. He suggested that amongst these two alleles, one allele is dominant in character and the other recessive. The combination of alleles determines the phenotype of a gene in an organism.
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...
01:18Dihybrid Crosses
Overview
02:27Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...