Introduction to Human Chromosomes
Rahul's Noteblog Notes on Genetics Introduction to Human Chromosomes
All cells in the human body, except germline cells, contributing to the human body are called somatic cells. The 46 chromosomes of human somatic cells constitute 23 pairs. Of the 23 pairs, 22 are alike in males and females and are called autosomes, while the remaining pair make the sex chromosomes: XX in females and XY in males. The largest chromosome is numbered 1 and the smallest chromosomes are numbered 22 and 23.
Members of a pair of chromosomes - called homologs or homologous chromosomes - contain matching genetic information. However, at any locus, they may have identical or slightly different forms of the same genes called alleles. One member of each pair of chromosomes is inherited from the father, and the other is inherited from the mother. The pairs of autosomes are microscopically indistinguishable from each other with exception of the sex chromosomes. Actually, the two X chromosomes in the female are microscopically indistinguishable, however, the sex chromosomes in the male are indistinguishable, namely, the X and Y chromosomes.
In females, one X chromosome is inherited from the father and the other X chromosome is inherited from the mother. In males, the Y chromosome is inherited from the father and the X chromosome is inherited from the mother.
Additional Readings:
Basic Genetics
1. Single-Gene Disorders
2. Population Genetics
3. Genetic Disease Transmission Probability
4. What is Cytogenetics?
5. Notes on Bloom's Syndrome
6. Introduction to Human Chromosomes
7. Life Cycle of Somatic Cells
Related Topics
1. Genetic and Developmental Disorders
2. Genetic Code, Mutations, and Translation
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