Genetics of Parenthood
The Genetics of Parenthood
Abstract: Why do people, even closely related people, look slightly different from each other? The reason for these differences in physical characteristics, or appearance, (called phenotype) is the different combination of genes (the genotype) possessed by each individual. All of your genes are segments of DNA located on your chromosomes. To illustrate the tremendous variety possible when you begin to combine genes, you and a classmate will establish the genotypes for a potential offspring. Your baby will receive a random combination of genes that each of you, as genetic parents, will contribute. Each normal human being has 46 chromosomes (23 pairs, which we call diploid or 2n) in each body cell. One pair of your chromosomes primarily determines your sex, thus, this pair is called the sex chromosomes. The other 22 pairs carry all the other genes that automatically determine everything else about you, thus, they are called autosomes. In forming the gametes (egg or sperm), one of each chromosome pair will be given by each parent, so these cells, or gametes, have only 23 single chromosomes (haploid or n). In this way, you contribute half of the genetic information (genotype) for the child; your partner will contribute the other half. Because we don 't know your real genotype, we 'll assume that you and your partner are heterozygous for every facial trait; heterozygous means that in each of your body cells you carry one copy of the gene for one type of body trait and another copy of the gene for a slight difference in that trait. Which one of the two available copies you contribute to your baby through sperm and egg is random, like flipping a coin. In this lab, we are keeping it simple - there are only 30 gene pairs and 30 inheritable traits represented, but in reality there are thousands of different gene pairs, and so there are millions of possible gene combinations!
Purpose: Several
Abstract: Why do people, even closely related people, look slightly different from each other? The reason for these differences in physical characteristics, or appearance, (called phenotype) is the different combination of genes (the genotype) possessed by each individual. All of your genes are segments of DNA located on your chromosomes. To illustrate the tremendous variety possible when you begin to combine genes, you and a classmate will establish the genotypes for a potential offspring. Your baby will receive a random combination of genes that each of you, as genetic parents, will contribute. Each normal human being has 46 chromosomes (23 pairs, which we call diploid or 2n) in each body cell. One pair of your chromosomes primarily determines your sex, thus, this pair is called the sex chromosomes. The other 22 pairs carry all the other genes that automatically determine everything else about you, thus, they are called autosomes. In forming the gametes (egg or sperm), one of each chromosome pair will be given by each parent, so these cells, or gametes, have only 23 single chromosomes (haploid or n). In this way, you contribute half of the genetic information (genotype) for the child; your partner will contribute the other half. Because we don 't know your real genotype, we 'll assume that you and your partner are heterozygous for every facial trait; heterozygous means that in each of your body cells you carry one copy of the gene for one type of body trait and another copy of the gene for a slight difference in that trait. Which one of the two available copies you contribute to your baby through sperm and egg is random, like flipping a coin. In this lab, we are keeping it simple - there are only 30 gene pairs and 30 inheritable traits represented, but in reality there are thousands of different gene pairs, and so there are millions of possible gene combinations!
Purpose: Several
References: Adapted from materials from Joan Carlson, Jack Doepke, Judy Jones and Randyll Warehime. Lewis, Rikki. 1994. Human Genetics: Concepts and Applications. Wm. C. Brown Publishers. Stine, Gerald J. 1989. The New Human Genetics. Wm. C. Brown Publishers.