Name ______Date ______

Traits controlled by single genes:

  1. Many ______traits are controlled by a single gene.
  2. These genes have two alleles - ______and ______.

Alleles:

  1. Each allele controls a different ______of a trait.

Affect of the Environment:

  1. The effects (or result) of genes are ______by the environment.
  2. Ex: ______can affect height. A diet that lacks proper nutrition can prevent a person from reaching their potential height.
  3. Other factors include living conditions and ______health care.

Male or Female?

  1. The gender of a baby is determined by ______located on ______.
  2. There are ______pairs of chromosomes in each of our cells.
  3. One pair of chromosomes are called ______chromosomes.
  4. Sex Chromosomes
  • The sex chromosomes determine whether a person is ______or ______.
  • The sex chromosomes are the only pair of chromosomes that ______always match.
  • Males: The two sex chromosomes do not match - ______.
  • Females: The two sex chromosomes match - ______.

SEX CHROMOSOMES

  • Since both of a female’s sex chromosomes are ______, ALL eggs carry one

______chromosome.

  • Males have two ______sex chromosomes, so sperm cells will

either carry an ______or a ______chromosome.

Sex-Linked Genes:

  1. Some human traits occur more often in one ______than the other.
  2. Sex-Linked Genes: Genes on the ______and ______chromosomes, whose alleles are passed from ______to offspring on sex chromosomes.
  3. In females, a ______allele on one X chromosome will mask (or hide) a recessive allele on the other X chromosome.
  4. In males, there is no matching allele on the ______and ______chromosome. As a result, any allele on the X chromosome will produce the ______in a male who inherits it.
  5. Because males only have on ______chromosome, males are more likely than females to have a ______-______trait that is controlled by a ______allele.
  6. Example of a Sex-Linked trait: Red-Green color blindness is controlled by a recessive allele on the ______chromosome. As a result, more ______are affected by color blindness than females.

Pedigrees:

  1. Are a chart or “______” that tracks which members of a family have a particular trait.
  2. Describe the following ______. The trait being traced is the presence of a widow’s peak.

Genetic Disorders:

  1. Genetic Disorders are an ______condition that a person inherits through genes or chromosomes.
  2. Genetic disorders are caused by ______. They can be ______and ______.
  • Cystic Fibrosis – a genetic disorder which the body produces too much mucus in the ______and ______. It is carried on the ______allele. The mucus makes it hard to breathe and digest food.
  • Sickle-Cell Disease – a genetic disorder that affects the production of ______in the blood. This causes blocked ______, which leads to difficulty breathing, pain, and weakness.
  • Hemophilia – a genetic disorder in which a person’s ______very slowly or not at all. This is a ______-______gene. A person can bleed to death from a minor cut.
  • Down Syndrome: a genetic disorder resulting from having an extra copy of chromosome ______.

Karyotype:

  1. A picture of all of the ______in the cell. The chromosomes are arranged in ______.

Advances in Genetics:

  1. Three methods that people have used to develop organisms with desirable traits:
  • Selective Breeding – breeding organisms with ______so that their offspring will have those traits.
  • ______- Crossing two individuals with similar or identical alleles and ______genetic disorders.
  • Hybridization – Breeding two genetically ______individuals.
  • Cloning – an organism that is ______to the organism from which it was produced. It can be done with ______or ______.
  • Genetic Engineering - ______from one organism are transferred into the ______of another organism. Used to produce ______, improve crops, and cure ______.

The Human Genome Project:

  1. The main goal of the human genome project is to identify ______in human DNA?