Genetics

My mother taught me about GENETICS...

"You are just like your father!"

OB35 understand that humans have inheritable and non-inheritable characteristics,

inheritable and non-inheritable characteristics

Write out a list of human characheristics divide this into Inherited and non inherited characteristics,Inherited characteristics are those that are passed down from your parents to their off spring. Non-inherited characteristics are those skills that you develop as a part of education either formally or informally at homeNatural eye colour Natural hair colour

Hair type Ear shape Ability to speak

Blood Type Height Ability to roll tongue

The following pictures show 2 different types of Lobe attachement. Both these types of lobe attachement are common, and both are inherited characteristics

Also how far your thumb bends back is also an inherited characteristic.

and that inheritable characteristics are controlled by genes

Enviromental factors and twins.

http://www.bbc.co.uk//gcsebitesize/science//genetics/genesinheritencerev4.shtml

What are genes ?

1st off we have the cell

in the Nucleus, we find pairs of Chromosomes

The human chromosome number is 46.

Chromosomes come in pairs, there are 23 chromosome pairs.

The last chromosome pair is the sex gene, x/x (female) or and x/y (male)

There are 22 distinctive, non sex chromosomes.

A chromosome consists of a single, very long DNA helix on which thousands of genes are encoded.

Genes are complex proteins and so we can say that

Chromosomes are made from DNA and Protein

http://www.bbc.co.uk/schools/gcsebitesize/science/21c/genetics/genesinheritencerev1.shtml

The Modal Human Cell has 22,000 genes

On each of the 46 chromosomes there are many genes, wikipedia has it all recorded

http://en.wikipedia.org/wiki/Chromosome#In_humans

How genes select attribute for characteristic

OB36 recall that genes are located on chromosomes and that in a human there are 23 pairs of chromosomes, which are located in the nucleus

Down syndrome is caused by a triple copy of chromosome 21,

which leads to a number of cognitive and physical delays.

Trisomy 21 (nondisjunction) Down syndrome is usually caused by an error in cell division called "nondisjunction."

Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual two.

Prior to or at conception, a pair of 21st chromosomes in either the sperm or the egg fails to separate.

OB37 recall that chromosomes are made of DNA and protein.

Th

http://www.sciencemuseum.org.uk/WhoAmI/FindOutMore/Yourgenes.aspx

Two strands of DNA are walking down the street,

and one says to the other:

"Do these genes make me look big?"

In the mid-nineteenth century, an Augustinian monk named Gregor Mendel made a simple observation: offspring tends to look like its parents.

He hypothesized that there must be a unit of inheritance (now known to be a gene) that would allow traits to be passed down in such a predictable way. With no knowledge of chromosomes or genes, Mendel set up an experiment to study heredity. Pea plants were chosen for their ease of manipulation (controlling pollen) and quick generation time.

Mendel noted flower color and position, stem length, seed shape and color, and pod shape and color. To keep this post simple, we’ll focus only on seed shape.

In the first generation (F0), Mendel crossed a purebred plant with wrinkled peas with a purebred plant with smooth peas. The resultant progeny (F1 generation) all had smooth peas. Upon allowing that F1 to self-pollinate, the wrinkled pea trait reemerged in F2, though smooth peas were still the most common, by a ratio of 3:1. These observations led Mendel to two important principles: the law of segregation, and the law of independent assortment.

The law of segregation states that each parent has two versions of a trait to pass on (known as an allele). Random chance determines which alleles get passed on.

The law of independent assortment states that different alleles get passed independently from each other. That is, seed shape has nothing to do with flower color, which is also independent from stem length. While linkage does exist, alleles on different chromosomes will be passed on independently.

While Mendel is now hailed as the father of all genetics, his initial publication in 1866 went largely unnoticed until the early 1900s, after his death.

For more information: http://anthro.palomar.edu/mendel/mendel_1.htm

A really nice piece based on the work of gregor mendel, hybrids & cross-pollination

http://anthro.palomar.edu/mendel/mendel_1.htm

downes syndrome? extra chromosome ??

Many problems that individual humans live with are due to chromosome problems

http://www.marchofdimes.com/baby/birthdefects_chromosomal.html