19_GeneticsFinalized

19_GeneticsFinalized - Genetics Genetics has a pronounced...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Genetics
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Genetics Click here to go back to LOM Genetics: the molecular basis of why you look and feel the way you do Does that guy or girl you admire have cute dimples when they smile? Can you roll your tongue? Can your parents or your siblings? Do you know your blood type? Is it the same as your parents so that you could give them blood if they needed it? Is there a disease that runs in your family that you are concerned could affect you? Do you know someone with an inherited disease even though no one else in their family has it? Each one of these questions is based on genetics. The genes you received from your parents play a major role in who you are, in a addition to external factors that contribute to your development. In this e-module we will explain the basis for the following: 1. How does having a specific gene translate to an outward trait? 2. What are the basic principles of inheritance? 3. How can we determine what traits parents can or will pass on to their children? 4. What are genetic diseases and how are they passed from one generation to the next?
Background image of page 2
Click here to go back to LOM Table 1: This small eample of various phenotypes is determined y the presence of asence of various alleles Figure 1: Genotypes and Phenotypes of the Dominant Recessive trait Dimples Click for Larger Image Click for Larger Image Genotype to Phenotype (from genes to traits) Recall that chromosomes contain all the genetic information of an organism. Chromosomes consist of base pairs of DNA that may be grouped into genes. It is the expression of these genes that leads to outward traits, including physical appearance: hair color, skin color, height, and even dimples. Every cell in your body has two copies of each chromosome (one from mom and one from dad), and thus two copies of every gene. These copies may have slight differences between them: different versions of the same gene are known as alleles. The particular pair of alleles you inherited from your parents is known as your genotype, while the outward appearance that results from the expression of these particular alleles is known as your phenotype. There are also specific terms, which refer to the combination of alleles that make up your genotype. If an individual has two copies of the same allele for a particular trait, that individual is said to be homozygous for that gene. If an individual has two different alleles for a trait, that individual is said to be heterozygous. Dimples- a dominant/recessive trait The presence of a particular allele does not ensure that a trait will be expressed in the individual who carries the allele. This is the case with dominant and recessive traits, for example, having or not having dimples. A dominant allele will always express its phenotype, even if only one copy is present, whereas a recessive allele must be present in two copies to show its phenotype. To simplify the discussion of a dominant/recessive genotype, abbreviations are used. A capital letter indicates a dominant allele, while a
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/21/2008 for the course BIOL 100 taught by Professor Lee during the Winter '07 term at San Diego State.

Page1 / 20

19_GeneticsFinalized - Genetics Genetics has a pronounced...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online