The probability that a certain trait will occur in the offspring of two individuals can be determined by knowing how genes are distributed in meiosis and the combinations in which they can come together at fertilization.
From the moment of conception, a human cell is diploid, containing two copies of each of the 23 different chromosomes. Chromosome charts called karyotypes are used to display the 23 chromosome pairs in size order (fig. 24.4). Pairs 1 through 22 are autosomes (aw'to-somz), which are chromosomes that do not carry genes that determine sex. The other two chromosomes, the X and the Y, determine sex and are called sex chromosomes. They are discussed later in the chapter in the section titled "Matters of Sex."
Brain 67,679 Smooth muscle 297
Blood cells 23,505 Skeletal muscle 4,693 Breast 4,001
Pancreas 5,534 Gallbladder 3,754 Small intestine 1,009 Ovary (women) 3,848
Uterus (women) 6,392
Salivary gland 186 Parathyroid glands 197 Thyroid gland 2,381 Esophagus 194
Predicted Distribution of Human Genes' Cellular Roles
Skin 3,043 Kidney 3,213
Prostate gland (men) 7,971
Testis (men) 7,117
Cell division/ DNA synthesis
Cell signaling/ communication
motility Cell/organism defense/ homeostasis
Was this article helpful?
This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.