Inheritance


 * patterns in heredity can include anything from dominant and recessive, to autosomal and X-linked.**
 * **Autosomal**: the gene responsible for the phenotype is located on one of the pairs of 22 autosomes.
 * **X-linked**: the gene that encodes for the gene is located on the X chromosome
 * **Dominant genes:** conditions that are meanifest in the heterozygotes
 * **Recessive**: Conditions are only manifest in individuals who have two copies of the mutant allele

Mendel's Principles 1.) the traits an organism inherits are determined by its genes. The genes are given to the offspring by its parents 2.) When there are two alleles, or different types of the same trait, the dominate trait will become present, if there are two dominant alleles or one dominant allele and one recessive allele. 3.) Alleles of the same gene commonly perform independent assortment, or segregate independently from one another. 4.) independent assortment randomly determines which alleles of each trait the offspring will inherit 5.) for each gene there are different versions - as already stated, there is one dominant form and one recessive form. - different forms of the same trait are known as alleles

here in this picture, you can see independent assortment occur in metaphase I, and in metaphase II. This is one of Mendel's principles. They align across the metaphase plate randomly in metaphase I, as well as in metaphase II. This produces unique gametes, as you can see below... for further clarification on this watch this video.......

http://www.youtube.com/watch?v=Y48ZO0WyPGc (please note that there is extra information that what is needed for our level of studies. However, this does give the reader further visual and audio clarification on many of these points.)

This next video gives the viewer great description and visualization of all basic aspects of inheritance and genetics... http://www.youtube.com/watch?v=eEUvRrhmcxM&feature=channel (please start watching at 2:30!) visit 2:30 for descriptions on alleles (dominant vs. recessive.) visit 4:44 for information on the differences on homozygous and heterozygous and how an organism can inherit homozygous and heterozygous traits. visit 6:37 on even further clarification on dominant vs. recessive alleles and which traits show. Visit 11:53 for information on punnett squares

Karyotypes

Karyotypes are basically a picture of a person's chromosomes. Karyotypes can show what changes might have occured in their chromosomal patterns.

for example... Down Syndrome occurs when a person has an extra 21st chromosome. In the picture below, you can see that there are three 21st chromosomes...



to see a visual of a person's karyotype and read more info on karyotypes, see these links... http://www.chromosome18.org/AboutGenetics/BasicGenetics/WhatisaKaryotype/tabid/120/Default.aspx http://downsyndrome.about.com/od/downsyndromeglossary/g/karyotypedef_ro.htm http://en.wikipedia.org/wiki/Karyotype