Hitchhiker's thumb may be an inherited condition with a genetic link. Some people with hitchhiker's thumb may have acquired two recessive copies, or alleles, of the gene that determines thumb straightness. This means that the trait for hitchhiker's thumb was present in both parents of the person born with it.

Why is a hitchhiker's thumb called a hitchhiker's thumb?

A total of 450 families were studied. A protractor was used to measure the angle of people's thumbs. The researchers gave the name “hitchhiker's thumb” to the thumbs that could bend at an angle equal to or greater than 50 degrees. They noted that many people had one hitchhiker's thumb and one straight thumb.

Is hitchhiker's thumb a Mendelian trait?

Though the 1949 study was reported from X-ray. Glass and Kistler concluded the Hitchhiker's to be a simple Mendelian trait. That is people with the Hitchhiker's thumb have two copies of the recessive “hitchhiker's gene” (H offspring).

How is the hitchhiker's thumb represented?

Some people have "hitchhiker's thumbs," which bend backwards with a large angle between the two segments (phalanges). The myth is that there are just two kinds of thumbs, straight thumbs (S) and hitchhiker's thumbs (H), and the trait is controlled by a single gene with two alleles, with the allele for S being dominant.

What chromosome is hitchhiker's thumb found on?

Temtamy preaxial brachydactyly syndrome

There is evidence the disease is caused by homozygous mutation in the CHSY1 gene on chromosome 15q26.

Hitchhikers thumb or bendy thumb meaning in palmistry

19 related questions found

What are murderers thumbs?

Stub thumbs or brachymegalodactylism, a term coined by Hefner (i924), refers to the condition of having an abnormally or disproportionately short thumb on one or both hands. This anomaly has been recognized for many years and among palm readers and fortune tellers it has been called 'murderer's thumbs'.

Is Widow's Peak dominant?

Most genes have two or more variations, called alleles. For example, the gene for hairline shape has two alleles – widow's peak or straight. ... For example, the allele for widow's peak is dominant and the allele for straight hairline is recessive.

Is curly hair dominant or recessive?

Curly hair is considered a “dominant” gene trait. Straight hair is considered “recessive.” To put that in simple terms, that means that if one parent gives you two curly haired genes and the other parent gives you a pair of straight-haired genes, you'll be born with curly hair.

How rare is a double jointed thumb?

Hypermobility (more commonly called being double-jointed) affects about 20% of people.

Why do some people's fingers bend back?

Physicians and researchers call it joint hypermobility or joint laxity, and it simply means that someone is able to move their joints farther than most people can. Most of us can bend our thumbs backwards a few degrees, but some can bend it farther.

What is it called when you have a wide thumb?

In addition to our thumbs being pretty stumpy, those of us who have clubbed thumbs also have wider-than-average, shorter-than-average thumbnails, and they have no backward arch to them.

Why is my thumb curved?

Hitchhiker's thumb is otherwise known as distal hyperextensibility of the thumb. This is because of the genetic traits that make a person bend his thumb backward while stretching. The distal joint plays an important role in keeping the thumb straight.

Is PP genotype or phenotype?

There are three available genotypes, PP (homozygous dominant ), Pp (heterozygous), and pp (homozygous recessive). All three have different genotypes but the first two have the same phenotype (purple) as distinct from the third (white).

Is hitchhiking illegal in USA?

Today, hitchhiking is legal in 44 of the 50 states, provided that the hitchhiker is not standing in the roadway or otherwise hindering the normal flow of traffic. Even in states where hitchhiking is illegal, hitchhikers are rarely ticketed.

How far are your fingers supposed to bend back?

These joints allow for fine motor control, and in most people can flex about 45 or 50 degrees, and more for some when the finger is fully bent. The DIP joint can also extend or bend backwards anywhere from 10 to 25 degrees. The most proximal finger joints are called the metacarpophalangeal joints, or MCP for short.

What does it mean if you can touch your thumb to your wrist?

This is a sign of Hypermobility. Test it for yourself – Place your hand up vertically like this, bend your hand forward, grab your thumb, then see if you can touch your thumb back to your wrist. Some people like Alexa can touch their thumb against their wrist or get very close to it as well.

Is hypermobility linked to ADHD?

ADHD is also associated with generalised joint hypermobility: One study reported generalised hypermobility in 32% of 54 ADHD patients, compared to 14% of controls. (Doğan et al. (2011).

Is hypermobility linked to autism?

In addition, a 2016 study performed in Sweden indicated that people with EDS are more likely to have a diagnosis of autism than individuals without the condition. Other research has also shown that autistic people have higher rates of joint hypermobility in general, a major feature of EDS.

Is triple jointed rare?

Hypermobile joints are common and occur in about 10 to 25% of the population, but in a minority of people, pain and other symptoms are present. This may be a sign of what is known as joint hypermobility syndrome (JMS) or, more recently, hypermobility spectrum disorder (HSD).

What's the rarest hair type?

Hair type 1A is super-straight. It doesn't even hold a curl! 1A is the rarest hair type. It is usually found on people of Asian descent.

What ethnicity does curly hair come from?

In sub-Saharan Africa, genes favour tight, curly hair. But in east Asia, mutations have led to straighter, thicker hair. In Europe, other mutations brought wavy and straw-coloured hair.

Why is curly hair pretty?

In my opinion, curly hair is attractive because it is spontaneous and unpredictable. There is something beautiful about it's independence. Your curls will not conform to societal pressure and they will not acquiesce to any attempts to tame them. ... Curly hair is playful and fun.

What nationality has a widow's peak?

Why is it called a widow's peak? The term “widow's peak” may be a holdover from 18th-century England. Tradition was that when a husband died, his wife would wear a black triangular hat or hood with the point falling in the middle of the forehead.

How are traits inherited?

Inherited traits are passed from parent to offspring according to the rules of Mendelian genetics. Most traits are not strictly determined by genes, but rather are influenced by both genes and environment.

How rare is widow's peak?

A study of women conducted by Nusbaum and Fuentefria in 2009 found that 81% had a widow's peak, but it is unclear what their criteria were in this study; Smith and Cohen's 1973 study on male medical students found that only 3% had widow's peaks, suggesting either high variation between genders or scholarly disagreement ...