X and Y chromosomes determine biological sex in humans; XX is typically female and XY male.
The Y chromosome carries SRY, which triggers male development, and the X carries many genes unrelated to sex. Females are XX, males XY, so the father's sperm determines the sex of the child.
Birds use a ZW system where the female is heterogametic; some reptiles use temperature to determine sex.
X and Y chromosomes determine biological sex in humans; XX is typically female and XY male.
Sex Chromosomes is one of the 54 topics in Genetics. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Sex-Linked Inheritance, X-Chromosome Inactivation, Turner and Klinefelter Syndromes.
Red-green colour blindness is common in males because they have only one X.
Sex Chromosomes is a Beginner topic, so no earlier topic is required. Other Beginner topics in Genetics that pair well with it include Heredity, Gene, Allele.
The closest topics to Sex Chromosomes are Sex-Linked Inheritance, X-Chromosome Inactivation, Turner and Klinefelter Syndromes, Chromosomes. Comparing them side by side is a good way to see how the ideas connect.
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Sex Chromosomes. To practise the whole of Genetics, use the Genetics quiz.
Sex Chromosomes: X and Y chromosomes determine biological sex in humans; XX is typically female and XY male. Sex-Linked Inheritance: Genes on the X chromosome show different patterns in males and females, as with red-green colour blindness. Read both side by side and note what each one explains.
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Sex-Linked Inheritance and explain the difference aloud. Finally, take the Genetics quiz and come back to this page for any question you miss.
Genes on the X chromosome show different patterns in males and females, as with red-green colour blindness.
🧬 GeneticsOne X chromosome in each female cell is silenced as a Barr body to equalise gene dosage.
🧬 GeneticsSex chromosome aneuploidies: Turner is XO and Klinefelter is XXY.
🧬 GeneticsThread-like structures of DNA and protein carrying genes; humans have 46 in 23 pairs.
🧬 Genetics