sex chromosome | genetics | Britannica.com
Posted: July 1, 2017 at 4:45 pm
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 comprise one pair of the total of 23 pairs of chromosomes. The other 22 pairs of chromosomes are called autosomes.
Individuals having two X chromosomes (XX) are female; individuals having one X chromosome and one Y chromosome (XY) are male. The X chromosome resembles a large autosomal chromosome with a long and a short arm. The Y chromosome has one long arm and a very short second arm. This path to maleness or femaleness originates at the moment of meiosis, when a cell divides to produce gametes, or sex cells having half the normal number of chromosomes. During meiosis the male XY sex-chromosome pair separates and passes on an X or a Y to separate gametes; the result is that one-half of the gametes (sperm) that are formed contains the X chromosome and the other half contains the Y chromosome. The female has two X chromosomes, and all female egg cells normally carry a single X. The eggs fertilized by X-bearing sperm become females (XX), whereas those fertilized by Y-bearing sperm become males (XY).
Read More on This Topic
sex: Sex chromosomes
In most species of animals the sex of individuals is determined decisively at the time of fertilization of the egg, by means of chromosomal distribution. This process is the most clear-cut form of sex determination. When any cell in the body divides, except during the formation of the sex cells, each daughter cell receives the full complement of chromosomes; i.e., copies of the two sets...
Unlike the paired autosomes, in which each member normally carries alleles (forms) of the same genes, the paired sex chromosomes do not carry an identical complement of genetic information. The X chromosome, being larger, carries many more genes than does the Y. Traits controlled by genes found only on the X chromosome are said to be sex-linked (see linkage group). Recessive sex-linked traits, such as hemophilia and redgreen colour blindness, occur far more frequently in men than in women. This is because the male who inherits the recessive allele on his X chromosome has no allele on his Y chromosome to counteract its effects. The female, on the other hand, must inherit the recessive allele on both of her X chromosomes in order to fully display the trait. A woman who inherits the recessive allele for a sex-linked disorder on one of her X chromosomes may, however, show a limited expression of the trait. The reason for this is that, in each somatic cell of a normal female, one of the X chromosomes is randomly deactivated. This deactivated X chromosome can be seen as a small, dark-staining structurethe Barr bodyin the cell nucleus.
The effects of genes carried only on the Y chromosome are, of course, expressed only in males. Most of these genes are the so-called maleness determiners, which are necessary for development of the testes in the fetus.
Several disorders are known to be associated with abnormal numbers of sex chromosomes. Turners syndrome and Klinefelters syndrome are among the most common of these. See also X trisomy; XYY-trisomy.
sex chromosome disorder of human females, in which three X chromosomes are present, rather than the normal pair. More common than Turners syndrome, where only one X chromosome is present, X-trisomy usually remains undetected because affected individuals appear normal, experience puberty,...
relatively common human sex chromosome anomaly in which a male has two Y chromosomes rather than one. It occurs in 1 in 5001,000 live male births, and individuals with the anomaly are often characterized by tallness and severe acne and sometimes by skeletal malformations and mental...
the sum of features by which members of species can be divided into two groupsmale and femalethat complement each other reproductively.
Follow this link:
sex chromosome | genetics | Britannica.com
- Male roundworms are picky when choosing a mate, new research finds - Phys.org - March 12th, 2024
- Male fertility is declining. Here's what the latest research shows as to why - Yahoo Eurosport UK - March 12th, 2024
- Protein integral to sperm development and male fertility identified - EurekAlert - February 23rd, 2024
- The Y Chromosome Is Vanishing. A New Sex Gene May Be The Future of Men. - ScienceAlert - February 23rd, 2024
- Embracing the Bald: The Journey of Acceptance and the Battle Against Male Pattern Baldness - BNN Breaking - February 23rd, 2024
- Fruit flies give further insight into evolution of male genitalia driven by sexual selection - EurekAlert - February 5th, 2024
- Massive genetic study estimates the chance of dying from prostate cancer - Medical Xpress - January 28th, 2024
- Lean Gene Reviews (USA) Does This Weight Loss Supplement Work? LeanGene Ingredients, Price, Where to Buy? - Outlook India - April 8th, 2023
- The biggest shock was not having a uterus the film about intersex beauty queen Sharon-Rose Khumalo - The Guardian - March 23rd, 2023
- Male Definition & Meaning | Dictionary.com - January 25th, 2023
- Male Genitalia Pictures, Anatomy & Diagram | Body Maps - Healthline - January 25th, 2023
- 15 Alpha Male Traits Characteristics of Real Alpha Males - January 25th, 2023
- The 15 Best Sex Toys for Men, According to Experts - SELF - January 25th, 2023
- Diabetes is increasing in younger population, finds study: Doctors share early signs that might help in early medical intervention - Times of India - January 25th, 2023
- Sexual dimorphism - Wikipedia - December 28th, 2022
- Why Do Men Go Bald: Male Baldness Causes, Treatment, Prevention - December 28th, 2022
- African Americans - Wikipedia - December 28th, 2022
- Talking Glossary of Genetic Terms | NHGRI - Genome - December 12th, 2022
- Risk Factors for Breast Cancer in Men - American Cancer Society - December 12th, 2022
- We have the killers DNA, we just need a name: Genetic game changer offers hope for near-unsolvable Ontario cold cases - Toronto Star - December 12th, 2022
- Hair loss - Symptoms and causes - Mayo Clinic - November 26th, 2022
- Cell Size and Scale - University of Utah - November 26th, 2022
- We created the world's first donkey embryo using IVF in a bid to save species from extinction - The Conversation - November 18th, 2022
- Male infertility - Diagnosis and treatment - Mayo Clinic - October 16th, 2022
- Dangerous Male Sex Pills - CBS News - October 16th, 2022
- Drone (bee) - Wikipedia - October 16th, 2022
- Prestigious award advances OHSU research on impact of drug use over generations - OHSU News - October 16th, 2022
- Breast Cancer Awareness Month: The importance of getting to know your lemons - Bothell-Kenmore Reporter - October 16th, 2022
- Identification of hub genes and candidate herbal treatment in obesity through integrated bioinformatic analysis and reverse network pharmacology |... - October 16th, 2022
- Behind this Nobel prize is a very human story: theres a bit of Neanderthal in all of us - The Guardian - October 16th, 2022
- Column One: Why this UCLA professor is studying female animals to gain insights into women's health - Los Angeles Times - October 16th, 2022
- Books wrap: Simone Kaho on her new poetry collection and PTSD; a conversation with Richard Wolfe; and more - New Zealand Herald - October 16th, 2022
- The 2016 WHO Classification of Tumours of the Urinary System and Male ... - October 8th, 2022
- How to Tell If a Squirrel Is Male or Female | Sciencing - October 8th, 2022
- The Genetic Drivers Of Longevity In Mice, Humans And Worms - Science 2.0 - October 8th, 2022
- A Guide To The Best Fertility Supplements And Vitamins For Men - Forbes - October 8th, 2022
- Early Signs Of Male Plant And Female Plant-How To Identify The Difference? - The Island Now - October 8th, 2022
- Why Not All 'House of the Dragon' Mixed Race Targaryens Are Blonde - Newsweek - October 8th, 2022
- Study on the interaction preference between CYCD subclass and CDK family members at the poplar genome level | Scientific Reports - Nature.com - October 8th, 2022
- Calcium-Channel Blocker and Adenosine Modulator Use and Risk of Hospitalization in Bipolar Disorder - Psychiatric Times - October 8th, 2022
- Israel, A Pioneer In Agriculture Of The Future - I24NEWS - i24NEWS - October 8th, 2022
- Results: Limousin society's 50th anniversary show and sale - Agriland - October 8th, 2022
- Drug resistance and population structure of Plasmodium falciparum and Plasmodium vivax in the Peruvian Amazon | Scientific Reports - Nature.com - October 8th, 2022
- Do Supplements Help Hair Growth? We Asked An Expert - SheFinds - October 8th, 2022
- Genomic imprinting - Wikipedia - September 30th, 2022
- BRCA beyond breast cancer: links to prostate, pancreatic, other tumors - The Columbus Dispatch - September 30th, 2022
- Severe COVID-19Related Outcomes Found Worse in Men With RA - Medscape - September 30th, 2022
- Let the Bees Tell You. On the Holy Bible (For Beekeepers) of Buckfast Abbey - Literary Hub - September 30th, 2022
- Genetics | Ohio State Medical Center - September 5th, 2022
- Regular exercise may help women live longer, regardless of their genes - Medical News Today - September 5th, 2022
- Habsburg Jaw: The Horrific Consequences of 'Royal Inbreeding' in Europe - TheTealMango - September 5th, 2022
- Alpha Beast XL Reviews (USA & Canada): Is It Legitimate Or Scammer? Shocking Ingredients Alert! - Deccan Herald - September 5th, 2022
- Men More Prone to Cancer Than Women, But Why? - HealthDay News - August 11th, 2022
- For Some Dolphins, the Key to Mating is Rolling with a Tight, Noisy Crew - Scientific American - August 11th, 2022
- Sister's Liver, Mother's Kidney Helps Save Uttarakhand Man's Life - NDTV - August 11th, 2022
- Role of genetic testing in in-vitro fertilization - Express Healthcare - August 11th, 2022
- Protective effect of apolipoprotein E epsilon 3 on sporadic Alzheimer's disease in the Chinese population: a meta-analysis | Scientific Reports -... - August 11th, 2022
- PRC1-mediated epigenetic programming is required to generate the ovarian reserve - Nature.com - August 11th, 2022
- Ashton Kutcher and Autoimmune Disease Vasculitis - Healthline - August 11th, 2022
- ROCKET PHARMACEUTICALS, INC. Management's Discussion and Analysis of Financial Condition and Results of Operations (form 10-Q) - Marketscreener.com - August 11th, 2022
- Meet the Algae That Went from Male/Female to Hermaphroditic - The Scientist - August 3rd, 2022
- The Sex Appeal of Symmetric Songs | TS Digest | The Scientist - The Scientist - August 3rd, 2022
- Asexual Reproduction: Species Reproducing on Their Own are Susceptible to Dangerous Genetic Mutations - Nature World News - August 3rd, 2022
- Viewpoint: Why genetic engineering of livestock is compatible with the sustainable and human treatment of animals - Genetic Literacy Project - August 3rd, 2022
- Why Do We Get Old, and Can Aging Be Reversed? - Quanta Magazine - August 3rd, 2022
- New Feminist Considerations of Masculinity, Reviewed - The New Yorker - August 3rd, 2022
- Family at 'breaking point' amid difficulties caring for son with rare genetic disorder - The Mirror - August 3rd, 2022
- There are valid reasons so many Nebraska kids have spent their summers detasseling corn - Scottsbluff Star Herald - August 3rd, 2022
- Prehistoric roots of 'cold sore' virus traced through ancient herpes DNA - EurekAlert - August 3rd, 2022
- Funny Papers Again Column | Idiotologies vs The Review and Research Posse - King City Rustler - August 3rd, 2022
- 10 US Parks Where You Can Watch Wildlife In Its Natural Habitat - TheTravel - August 3rd, 2022
- Men Missing Y Chromosome Have High Heart Disease Risk Best Life - Best Life - July 26th, 2022
- Going to the Beach? Planning a Hike? Be Prepared: Men Will Be Much Hungrier! - Neuroscience News - July 26th, 2022
- THE BALANCED LIFE | Use common sense when digesting wellness advice | - The Voice of Pelham - July 26th, 2022
- Ecostani | Despite concerns, the Cheetah project is worth pursuing - Hindustan Times - July 26th, 2022
- To what extent human beings are morally responsible for the actions they take as a result of their innate and acquired influences - Teen Ink - July 26th, 2022
- How Fast Does Hair Grow? Know These Easy-Peasy Tips to Grow your Tresses - TheTealMango - July 26th, 2022
- BETTER KNOW A PREY-GO-NEESH: Up Close and Personal With Your New Condor Neighbors - Lost Coast Outpost - July 26th, 2022
- From the 'Burgh to the Gulf: Lions relocated in zoo breeding program - TribLIVE - July 26th, 2022
- Long Non-Coding RNAs ANRIL and HOTAIR Upregulation is Associated with | IJGM - Dove Medical Press - July 26th, 2022