Cells and Heredity Chapter 5: Humans Genetics and Genetic Technology Lesson 1: Human Inheritance

Human Genes Some traits are controlled by single genes that only have two alleles. Some single genes have multiple alleles. Some traits are controlled by many genes.

Single Genes with Two Alleles Examples: widow’s peak, dimpled chin. You either have these sort of traits or you don’t.

Single Genes with Multiple Alleles Example: human blood. There are 4 blood types: A, B, AB, and O. The type of blood you have depends on the combination of the two alleles you received from your parents.

Traits Controlled by Many Genes Example: human height. At least four different genes impact a person’s height, and each of those genes has several alleles.

Sex-Linked Genes The sex-chromosomes determine whether a living organism will be male or female. Females have two X chromosomes (XX), while males have mixed chromosomes (XY). Females always pass on an X chromosome to their offspring, but males can pass on either an X or a Y.

Sex-Linked Genes Males are more likely to express a sex-linked recessive trait. Only females can be carriers of sex-linked genes because they are the only one that carry two alleles for the same trait. Example: red-green colorblindness, a recessive trait.

Cells and Heredity Chapter 5: Humans Genetics and Genetic Technology Lesson 2: Human Genetic Disorders

Genetic Disorders Genetic disorder: an abnormal condition that a person inherits through genes or chromosomes. Caused by mutations, change in structure of chromosomes, or change in number of chromosomes.

Cystic Fibrosis Body produces thick mucus in lungs and intestines, making it hard to breathe. Two mutated alleles must be inherited, one from each parent.

Sickle-Cell Red blood cells are shaped like crescents instead of circles. They cannot carry as much oxygen as normal RBCs. A person with two sickle cell alleles will have the disease.

Hemophilia Blood clots very slowly or not at all. Occurs more commonly in males than females because it is sex-linked.

Down Syndrome There is an extra copy of chromosome 21. Usually occurs when chromosomes fail to separate during meiosis.

Pedigrees A pedigree is a chart that tracks which members of a family have a particular trait. Circles = females Squares = males Half-filled in = carrier Filled in = has trait

Karyotyping A karyotype is a picture of all of the chromosomes in a person’s cell. Detects the number of chromosomes in an organism’s cell.

Cells and Heredity Chapter 5: Humans Genetics and Genetic Technology Lesson 3: Advances in Genetics

Selective breeding The process of selecting organisms with desired traits to be parents of the next generation. has been used with several different plants and animals.

Selective breeding Inbreeding: crossing two individuals that have similar desirable characteristics. Results in very similar offspring Increases likelihood of recessive diseases Hybridization: crossing two genetically different individuals. Aims to have offspring that inherit the best qualities from both parents.

Cloning A clone is an organism that has exactly the same genes as the organism from which it was produced. Very easy to do this with many plants.

Genetic Engineering Genes from one organism are transferred into the DNA of another organism. Can be used for medicines, such as insulin. Many plants are genetically modified to survive harsher conditions and resist pests. Fairly new process that is controversial.

Cells and Heredity Chapter 5: Humans Genetics and Genetic Technology Lesson 4: Using Genetic Information

Human Genome Project A genome is the whole set of someone’s DNA. Scientists identified the DNA sequence of the entire human genome.

DNA Fingerprinting DNA can be taken from a cell and broken down into pieces, which creates a pattern called a DNA fingerprint. Only identical twins have the same DNA fingerprint. Can be used to identify unknown persons or tie people to a crime.

Genetic Discrimination Ethics is the study of principles about what is right and what is wrong, fair and unfair. This is very relevant in the medical world today, as medical professionals must keep genetic information private and cannot treat patients differently based on their genes.