What type of genetic trait is polydactyly?
Polydactyly is a type of genetic trait in humans where an individual has more than the typical number of fingers and/or toes. It is a dominant genetic trait, meaning that only one allele is required for an individual to be affected.
Polydactyly is an inherited trait, and is caused by gene mutations related to the HOX genes located on chromosome 7, which are involved in the formation of the digits. It can affect both the hands and the feet, and can occur in various forms, including having an extra digit, or two additional digits fused together to form an extra digit.
The severity and pattern of this trait can vary significantly, and can occur as a standalone condition, or as part of a genetic syndrome. It is estimated that between 1 in every 500 and 1 in every 1,000 live births presents with a form of polydactyly.
Some treatments are available to remove the extra digits, but this is usually elective and at the discretion of the patient.
Is polydactyly a monogenic trait?
No, polydactyly (the condition of having more than the standard number of fingers or toes) is not usually a monogenic trait, meaning it isn’t caused by a single gene. Including genetic mutations, certain birth defects, certain medical conditions, and even certain medications.
A number of autosomal dominant, autosomal recessive, and sex-linked genes have been associated with polydactyly. In addition, environmental factors such as maternal infections and dietary deficiencies have been linked to the condition.
Researchers speculate that somewhere between 40-60 percent of all cases of polydactyly are caused by a combination of genetic and environmental factors, rather than a single gene.
Is polydactyly caused by a recessive trait?
Yes, polydactyly is typically caused by a recessive trait. Polydactyly is a genetic disorder that causes an individual to be born with extra fingers or toes. In general, it is inherited as an autosomal recessive trait, meaning both parents must be carriers.
This is because the defective gene must be passed on by both parents in order for the disorder to be expressed. When both parents are carriers, there is a 25% chance their child will develop the condition.
Even if the individual does not show any signs of polydactyly, they may still be a carrier and pass the gene on to their children.
Is polydactyly inherited as an autosomal dominant trait?
Yes, polydactyly (the presence of extra digits on the hands or feet) is typically inherited as an autosomal dominant trait. This means that only one parent needs to have the gene for it to be passed down to the child.
In many cases, the extra digits are caused by a genetic mutation in the sporocyst hoD gene.
In some families, this trait may be inherited in an autosomal recessive manner, meaning both parents must carry the gene for it to be passed down. In either case, the chances that the trait will be passed on to the next generation will depend on the genetic makeup of the parents.
Additionally, the chances of passing down a dominant trait are usually higher than that of a recessive trait.
It’s important to note that while polydactyly is typically an inherited trait, it can also occur sporadically and without any family history of the condition. In these cases, the extra digits can be caused by environmental factors (e.g.
certain medications, nutritional deficiencies, etc.) during fetal development.
What is monogenic vs polygenic?
Monogenic traits are traits inherited from a single gene, on a single gene locus. Monogenic traits have a clear pattern of inheritance, with the same trait being inherited from both parents. These traits can be dominant or recessive, meaning that a single gene can produce a trait or not depending on whether it is from the dominant or recessive gene.
Common examples of monogenic traits include eye color, height, and flower color.
Polygenic traits are traits determined by a combination of several genes or multiple gene loci. Polygenic traits have a complex pattern of inheritance, meaning that the inheritance of a trait is not easily predicted since it depends on multiple loci.
These traits are considered quantitative traits since they involve the combination of several genes interacting in a complex manner to produce the trait. Common examples of polygenic traits include skin color, height, body mass index, and IQ.
What are examples of monogenic traits?
Monogenic traits are disorders and physical characteristics that are caused by an alteration of a single gene. Examples of monogenic traits include:
1. Duchenne muscular dystrophy: This genetic disorder is caused by a mutation in the dystrophin gene and is characterized by progressive muscle weakness and eventual loss of movement.
2. Huntington’s disease: Also known as Huntington’s chorea, this genetic disorder is caused by a mutation in the huntingtin gene and is characterized by the deterioration of mental and physical abilities.
3. Cystic fibrosis: This genetic disorder is caused by a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and is characterized by frequent respiratory infections, difficulty gaining weight, and difficulty breathing.
4. Marfan syndrome: This genetic disorder is caused by alterations in the FBN1 gene and is characterized by physical features such as long arms, legs, and fingers, and a tall, slender build.
5. Color blindness or color vision deficiency: This is a condition in which the person has difficulty seeing certain colors and is caused by mutations in various genes that are responsible for the development of the color-detecting cells in the retina.
What trait is polydactyly an example of both?
Polydactyly is an example of both a genetic trait (or condition) as well as a physical trait. It is a genetic condition that is usually inherited (although it can also occur randomly) that causes a person to have more than the “normal” number of fingers or toes.
The physical trait of polydactyly is visible, as the individual will have extra fingers or toes on each hand or foot. Polydactyly is a relatively common trait and its prevalence varies depending on a population’s ancestry.
While it may not necessarily have any functional benefit, having extra fingers/toes can be a source of pride or unique identity for the individual.
Is the polydactyly gene dominant or recessive?
The polydactyly gene is largely considered to be dominant. This means that a single copy of the gene is enough to produce the trait of polydactyly. It is believed to be caused by a variety of different genetic mutations, the most common of which is in the HOXD13 gene.
This gene plays an important role in the development of the limbs, and changes to its structure are known to cause the development of extra digits. Although polydactyly is mainly considered to be a dominant trait, there is also evidence to suggest that it can be inherited in a recessive manner as well.
In cases of recessive polydactyly, both parents would need to be carrying the mutated gene in order to pass it on to their children.
How is polydactyly passed down?
Polydactyly is a condition in which a person has more than the usual number of fingers or toes. The trait is inherited in an autosomal dominant pattern, meaning it is a dominant gene and can be passed down from parent to child even when only one parent has the trait.
A parent carrying one copy of the mutated gene has a 50% chance of passing along the condition to their child. If a person inherits two copies of the mutated gene, one from each parent, then the person will have even more extra fingers and toes.
Polydactyly is not linked with any other medical conditions, although people with extra fingers or toes may have medical problems related to the extra digits.
Can polydactyly skip a generation?
Yes, it is possible for polydactyly to skip a generation. Polydactyly is a condition which causes an individual to have extra fingers or toes, and it is a genetic trait. Polydactyly can occur due to a random genetic mutation, and it is possible that the mutation will not be passed down from the parent to the child, causing the condition to skip a generation.
Polydactyly can also be inherited, meaning it is passed down through a family’s DNA. In these cases, if the parent carrying the gene does not pass it down to the child, it will appear as if the condition has skipped a generation.
It is important to remember that when it comes to conditions like polydactyly, it is always best to seek a professional medical opinion for the most accurate diagnosis.
Who is most likely to get polydactyly?
Polydactyly is an abnormality of the hand or foot where one or more than five fingers or toes are present. It is most commonly found as a congenital birth defect, meaning it is present at birth. It is estimated that 1 in solely of all newborns present with polydactyly.
It is most common in certain ethnic groups and in those with a family history of the condition. A few of these groups include African American, Southeast Asian, and Native American. It tends to be an autosomal dominant inheritance type with equal occurrence in males and females.
Though the exact cause has yet to be determined, studies suggest it may be due to a random gene mutation or environmental factors. Polydactyly is usually harmless and typically doesn’t have any associated medical problems.
Some individuals may choose to have the extra digits removed while others may opt to leave them alone as they may provide improved robustness and dexterity.
What race is polydactyly most common in?
Polydactyly is most common among isolated populations in the United States, particularly among Native Americans, especially among groups from the Southeastern US and the Southwest US. Polydactyly is also more common among African Americans.
Studies have shown that approximately 4.6% of African American children display the trait, compared to 3.2% of Caucasians, 1.9% of Hispanics, and 1.3% of Asians. The trait is also found among those of Asian and Middle Eastern origin, as well as among other tribal and ethnically diverse populations.
Does polydactyly run in families?
Yes, polydactyly can run in families. Polydactyly is an abnormality of a person’s hands or feet that causes them to have more than five fingers or toes. It is a genetic condition, which means it can be inherited from a parent.
There are two different types of polydactyly that can run in families, autosomal dominant polydactyly and autosomal recessive polydactyly. Autosomal dominant polydactyly is when a single copy of an abnormal gene from one parent is enough to cause the condition.
Autosomal recessive polydactyly is when two copies of the same gene, one from each parent, are necessary for the condition to occur.
Families with a history of polydactyly should talk to their doctor or genetic counselor. They can advise the family on the risk of passing on the gene and determine whether genetic testing is appropriate.
In some cases, the extra digit can be surgically removed, but this is usually done for aesthetic reasons. There are only mild risks associated with the procedure, such as infection and scarring. Parents should consider all available options before making a decision.
Can polydactyly be detected before birth?
Yes, polydactyly can be detected before birth. Polydactyly is a congenital anomaly (birth defect) that is present in 1 in every 1,000 births, making it relatively common. It is caused by abnormal development of the embryonic tissues that form the hands and feet.
Ultrasound scans are able to detect this condition before birth. Features that suggest the presence of polydactyly include extra fingers and toes, wider than normal digits (fingers and toes), and large growth/lumps on the hands and/or feet.
Ultrasound can detect these features even in the first trimester of pregnancy. If polydactyly is detected on investigations such as ultrasound, then further investigations may be required with additional ultrasound scans, amniocentesis or fetal MRI.
Treatment for polydactyly usually involves surgery after birth to remove the extra digits so that the hand/foot can develop normally.