From Mendel to DNA. Learning Objectives What did Mendel’s experiments teach us about inheritance? What are DNA fingerprints? How are specific proteins made in the body?. Carried out breeding experiments with peas. Used pure strains of: round, wrinkled, green and yellow peas .
From Mendel to DNA
What did Mendel’s experiments teach us about inheritance?
What are DNA fingerprints?
How are specific proteins made in the body?
Mendel suggested that there were separate units of inherited material. He realised some characteristics were dominant over others and that they never mixed together.
A gene is a section of DNA coding for a particular feature.
e.g. eye colour, attached/unattached ear lobes, ability to roll tongue.
DNA is a chemical that stores your genetic material.
Structure of DNA
Each base is like one letter in a four-letter alphabet.
These letters make up 3 letter groups called codontriplets.
Each triplet is one piece of information.
‘DNA fingerprinting’ – a technique that uses the unique patterns in your DNA to identify you.
DNA fingerprinting – what are some of the uses?
Explain how DNA fingerprinting could be used to find out which one is the real father.
Inheritance in Action
How is sex determined in humans?
Can you predict what features a child might inherit?
Humans have 46 chromosomes – 23 from the mother and 23 from the father.
The complexity of an organism does not seem to be correlated with the number of chromosomes it has.
Fruit fly – 8
Kangaroo – 12
Human – 46
Chicken – 78
Fern - 1200
In 22 cases each chromosome in the pair is a similar shape and has genes carrying information about the same things. But one pair of chromosomes may be different – these are the sex chromosomes.
Chromosomes from a female
Chromosomes from a male
Pair 23 – the non-matching pair of chromosomes
Genetic diagrams are used to show possible outcomes of a particular cross. Dominant allele is shown by a capital letter, and a recessive allele by a lower case letter.
Inherited or not?