*** Genetics! ***

​This blog post will basically touch the simple facts, the history of genetics, etc.

 

 

1886: Gregor Mendel discovered that traits of offspring depend on the parents traits, which may be dominant or recessive. ( but this was somehow lost)

1902: Theodore Boveri & Walter Sutton used color to observe chromosomes 

1905: Nettle Stevens found out that all homologous chromosomes are the same except the ones that determines sex (X,Y)

1909: Thomas H Morgan made many important researches in fly genetics and linked analysis that apply to all diploid organisms

1941: Beadle and Tatum discovered that each gene encodes one protein

1944: Oswald Avery identified DNA as genetic material

1953: Rosalind Franklin and Maurice Wilkins showed that the DNA is a double helix, Thomas Watson and Frances Crick figured out that the base of the double helix enabled replication 

1970: Tamin and Baltimore found a enzyme used to clone genes 

1981: First transgenic mammals are made

1996: Iam Wilmut cloned the lamb Dolly from adult mammary gland tissue  

Genetics is the features and characteristics that make up an organism. 

 

 Your genetics decipher what you will look like, and your features.

 

There are many things you can learn about your genetics like your DNA and what factors are inside of it to make it important, also your genotype/phenotype, and what a recessive gene and dominant gene is.

 

Lets start simple:

 

DNA stands for Deoxyribonucleic acid. Your DNA is a molecule that carries all of your genetic information

 

Genotype describes what certain alleles are on a certain chromosome

 

Alleles are a form of a gene that play part on a specific chromosome, which controls a certain trait.

 

There are dominant and recessive alleles

 

Dominant alleles are upper case and usually the trait that comes out the most

 

Recessive is usually shown with an lower case letter, and in this allele it is usually the trait that does not show unless the organism is homozygous.

 

Homozygous just means that both of the alleles are either dominant or recessive

 

Heterozygous means that one of the alleles are dominant and one is recessive  

 

Phenotype is the physical characteristics of the gene

There are many ways that you can determine what exactly an offspring’s traits will be by using genotype. One way is to look at the alleles of the two organisms. Also if you really wanted to be accurate you will put them in a punnet square.

 

Punnet squares is just a fancy word to describe the separation of alleles to figure out what an offspring may look like, also to fish out the chances of having a certain child.

 

For example a mother and father are about to have a child they want a child with blue eyes. The mother has two alleles bb, which are homozygous. The father also has two alleles Gb, which are heterozygous. Knowing that the father has green eyes, because greens allele is dominant and blue is recessive you can figure out what is the chance of the child having blue eyes.  

By looking at this you can see that the child has a 50% chance of having green eyes or having blue eyes. But what if the father was also homozygous?

There would be no chance at the child being born with blue eyes. 

In the PSSA I do not know exactly what kind of questions will be asked, but make sure you do the study island and also look up a few things to make sure you understand such as:

Where your DNA gets its information from and what it is made up of and how its held together

How many chromosomes a human has (46)

Different types of gene disorders and also different types oh names for each type of gene

What kind of diseases are gene orientated

 


http://www.learner.org/interactives/dna/genetics.html
http://www.dnai.org/
http://www.nobelprize.org/educational/medicine/dna/
http://learn.genetics.utah.edu/content/begin/dna/builddna/

http://dnaandrna.com/RNA.html