Related Experiment Video
Updated: Jul 5, 2026
08:48
Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects
Published on: April 21, 2022
Fragmentation of DNA in morphologically normal human spermatozoa
Conrado Avendaño1, Anahí Franchi, Steven Taylor
1Department of Obstetrics and Gynecology, Jones Institute for Reproductive Medicine, Eastern Virginia Medical School, Norfolk, Virginia.
Fertility and Sterility
|April 29, 2008
Summary
In infertile men, even sperm with normal morphology can exhibit DNA fragmentation. This finding is crucial for understanding male infertility and optimizing fertility treatments.
Area of Science:
- Reproductive Biology
- Human Genetics
- Andrology
Background:
- Sperm DNA fragmentation is linked to male infertility.
- Assessing sperm morphology is a standard diagnostic tool.
- The relationship between normal morphology and DNA integrity requires further investigation.
Purpose of the Study:
- To evaluate DNA fragmentation in spermatozoa that appear morphologically normal.
- To determine if morphologically normal sperm in infertile men harbor DNA damage.
Main Methods:
- A prospective study was conducted at an academic tertiary center.
- Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-fluorescein nick-end labeling (TUNEL) assay and morphology assessment were used.
- Sperm samples from fertile, subfertile, and infertile men were analyzed.
Main Results:
- No DNA fragmentation was observed in morphologically normal sperm from fertile men.
- One subfertile sample showed DNA fragmentation in normal-appearing sperm.
- All infertile men exhibited DNA fragmentation in morphologically normal sperm, with a high proportion of damage.
Conclusions:
- Morphologically normal spermatozoa in infertile men, particularly those with teratozoospermia, may possess DNA fragmentation.
- This suggests that standard morphology assessment alone may not fully represent sperm DNA integrity in infertile populations.
Related Concept Videos
01:49Meiosis I
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 a...
01:41Spermatogenesis
Spermatogenesis is the process by which haploid sperm cells are produced in the male testes. It starts with stem cells located close to the outer rim of seminiferous tubules. These spermatogonial stem cells divide asymmetrically to give rise to additional stem cells (meaning that these structures “self-renew”), as well as sperm progenitors, called spermatocytes. Importantly, this method of asymmetric mitotic division maintains a population of spermatogonial stem cells in the male reproductive...
01:22Spermatogenesis
Spermatogenesis is a complex process that involves the development of sperm cells from undifferentiated stem cells in the seminiferous tubules of the testes. The process is essential for the production of mature and functional sperm cells that are capable of fertilizing an egg.
The process of spermatogenesis can be divided into mitosis, meiosis, and spermiogenesis. During mitosis, the spermatogonia or stem cells divide to produce two identical daughter cells, type A and B spermatogonia. Type-A...
The process of spermatogenesis can be divided into mitosis, meiosis, and spermiogenesis. During mitosis, the spermatogonia or stem cells divide to produce two identical daughter cells, type A and B spermatogonia. Type-A...
01:34What is Meiosis?
Meiosis is the process by which diploid cells divide to produce haploid daughter cells. In humans, each diploid cell contains 46 chromosomes, half from the mother and half from the father. Following meiosis, the resulting haploid eggs or sperm only contain 23 chromosomes; however, each of these chromosomes contains a unique combination of parental information that results from the meiotic process of crossing over.
Although meiosis shares similarities with mitosis—both rely on microtubules to...
Although meiosis shares similarities with mitosis—both rely on microtubules to...
01:36What is Meiosis?
Meiosis is the process by which diploid cells divide to produce haploid daughter cells. In humans, each diploid cell contains 46 chromosomes, half from the mother and half from the father. Following meiosis, the resulting haploid eggs or sperm only contain 23 chromosomes; however, each of these chromosomes contains a unique combination of parental information that results from the meiotic process of crossing over.
01:38Fertilization
During fertilization, an egg and sperm cell fuse to create a new diploid structure. In humans, the process occurs once the egg has been released from the ovary, and travels into the fallopian tubes. The process requires several key steps: 1) sperm present in the genital tract must locate the egg; 2) once there, sperm need to release enzymes to help them burrow through the protective zona pellucida of the egg; and 3) the membranes of a single sperm cell and egg must fuse, with the sperm...