Search results
May 30, 2024 · sex chromosome, either of a pair of chromosomes that determine whether an individual is male or female. The sex chromosomes of human beings and other mammals are designated by scientists as X and Y. In humans the sex chromosomes consist of one pair of the total of 23 pairs of chromosomes. The other 22 pairs of chromosomes are called autosomes.
- The Editors of Encyclopaedia Britannica
- Overview
- What are sex chromosomes for?
- What’s the difference between primary and secondary sex determination?
- What is a difference in sexual development (DSD)?
- Other frequently asked questions
- The bottom line
A chromosome is a DNA molecule that contains genetic material. Sex chromosomes are chromosomes that affect your sexual anatomy and reproductive development.
Most of us were raised with the idea that there are two sexes: male and female. We’re usually told that people with XY chromosomes are male and people with XX chromosomes are female.
It’s a lot more complicated than that.
Typically, there are 46 chromosomes in each human cell. This usually includes a pair of sex chromosomes and 22 pairs of autosomes. Autosomes are all chromosomes that are not sex chromosomes.
Many people are born with variations in sex chromosomes, also called X and Y variations or sex chromosome aneuploidy (SCA).
People with an SCA may have one X chromosome, XXY chromosomes, XXX chromosomes, and so on.
Sex chromosomes typically determine the development of your reproductive organs and your secondary sex characteristics.
For example, your sex chromosomes may determine:
•the hormones your body produces
•whether you have ovaries or testes
•the development of breast tissue
Having certain sex chromosomes may also make you more susceptible to specific health conditions. For example, hemophilia A and B are sex-linked conditions more likely to appear in people with XY chromosomes.
Primary sex determination depends on chromosomes. Secondary sex determination depends mostly on hormones.
Primary sex characteristics include the gonads, which are the glands that produce reproductive hormones in the body.
Secondary sex characteristics are determined by the hormones the gonads secrete. These characteristics include your body’s phenotype (how it looks) outside of the reproductive system.
Examples of secondary sex characteristics include:
•enlarged breasts
•wider hips
Many people have a difference in sexual development (DSD), which is also called intersex. “DSD” is a term that describes chromosomes, sex characteristics, and anatomy that can’t be defined as exclusively male or female.
As many as 1 in 100 people are born with a DSD.
Not everyone with a DSD has variations in sex chromosomes. Some people with DSDs may have XX or XY chromosomes. But they might also have X and Y variations or SCA.
Variations in sex chromosomes can include:
•45,X (Turner syndrome)
•47,XXY (Klinefelter syndrome)
How many sexes are there?
If you look this up, you’ll undoubtedly find a variety of opinions on the matter. Some say there are only two sexes, while others say there are an infinite number of sexes. It depends on your definition of sex: What makes a specific phenotype a “sex”? How do you determine the difference between a sex category and a sex variation? It’s hard to say. Many biologists assert that sex is a spectrum and not a binary, meaning there are many variations in sex and not simply two exclusive categories. Gender and sex are different things — but gender is also not a binary.
How many people are born intersex?
As many as 1 in 100 people are born with a difference in sex development (DSD), which is another term for intersex. According to the Intersex Society of North America, about 1 in 1,500 to 1 in 2,000 people are determined intersex at birth. However, some intersex people only find out about their DSD later on in life, like at puberty or as an adult. It’s even possible to have intersex traits and never know. This number depends on how you define “intersex.” Many people have variations in sex differences that are not apparent to others. As such, some clinicians might not consider them intersex.
What are karyotypes?
Your karyotype is your complete set of chromosomes. A karyotype is used to visualize the appearance of your chromosomes, including the size, number, and shape of the chromosomes.
Sex chromosomes determine the development of your gonads. But sex chromosomes are a lot more complex than most people think.
While we’re typically taught that there are only two sex chromosome types — XX and XY — the truth is there are more variations than that.
- Sian Ferguson
Early in female embryonic development, in cells other than egg cells, one of the X chromosomes is randomly and permanently partially deactivated: In some cells, the X chromosome inherited from the mother deactivates; in other cells, it is the X chromosome inherited from the father. This ensures that both sexes always have exactly one functional ...
In mammals, including humans, there is a pair of chromosomes that define the genotypic sex of that organism. These chromosomes are labeled X and Y and having 2 X chromosomes is a genotypic female and having X and Y is a genotypic male. So, an X linked gene is a gene that is found on an X chromosome.
- Hi Tanya, my understanding is that XX individuals with an SRY translocation (who develop as male-bodied) may need hormone supplementation at pubert...
- I'm not an expert on this, but my understanding is that SRY† is (usually) sufficient for embryonic testis formation and that the hormonal effects o...
- Sex linkage referes to a gene being linked to (or "on") a sex chromosome. Gene linkage refers to two genes that are on the same chromosome, and are...
- Any time you have dominant and recessive alleles of a gene it is only the dominant allele that gets expressed. There doesn't have to be a second al...
- Yes, that is correct.
- Blood type is not a sex-linked trait. Its an autosomal trait determined by gene I located on chromosome 9. The gene I has 3 allelic forms, Ia, Ib a...
- well, depends on if disease is dominant or recesive and what the mother has
- Hemizygous is a term used to describe an individual who has only one member of a chromosome pair or chromosome segment rather than the usual two.
3 days ago · Definition. A sex chromosome is a type of chromosome involved in sex determination. Humans and most other mammals have two sex chromosomes, X and Y, that in combination determine the sex of an individual. Females have two X chromosomes in their cells, while males have one X and one Y.
Humans have two kinds of sex chromosomes, an X and a Y. The mix of chromosomes you have plays a big part in determining how you will develop. People usually have two sex chromosomes. Typically, embryos with one X and one Y chromosome develop into males. And those with two X chromosomes usually become females. We get one sex chromosome from our ...
People also ask
Are chromosomes male or female?
Do humans have two sex chromosomes?
What are sex chromosomes?
How many chromosomes are in a human cell?
Aug 15, 2020 · Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique. The term chromosome comes from the Greek ...
