Conservation Genetic strategies

1. Conservation Genetic strategies Bio3B

2. Genetic strategies Genetic strategies involve manipulation of DNA or gene pools eg breeding programs, genetic engineering, DNA profiling, seed banks

3. Captive breeding programs • How it works Animals are bred in captivity (zoos or parks), then may be released back into the wild, or into reserves or parks. This may involve artificial insemination, in vitro fertilisation and or hand rearing of offspring Plants may be produced by tissue culture, cuttings or seed. Seed banks may store seed to maintain genetic diversity • Examples Numbats, chuditch, western swamp tortoise are bred then released into managed reserves (fenced areas where baiting programs have removed introduced predators eg foxes & cats) Other species bred at the Perth zoo include orang utan, gibbon, rhino Plants – Wollemi pine (ancient remnant of pines found in the Blue mountains – propagated by tissue culture, Jarrah resistant to dieback being propagated by seed and tissue culture • Benefits Maintains existence & genetic diversity of species under threat in natural habitats • Knowledge needed for effective use Reproductive technology (eg AI, IVF, tissue culture) Life cycle & breeding habits of species involved (eg apes must be taught how to raise young by seeing mothers or sisters doing it) , Symbiotic associations (eg orchids have a mutualistic relationship with fungi, Australian Christmas trees are semi parasitic on wattles, callistemons or eucalypts)

4. Development of new strains of crops/food animals • How it works new strains of high yield or disease/pest resistant crops/food animals are bred or genetically engineered • Examples Higher yield hybrid cereals eg rice, wheat Cereals that tolerate lower rainfall or salinity eg wheat Disease resistant crops eg wheat that resists rust Pest resistance – either by breeding or by inserting DNA eg GM canola & cotton Pigs and chickens that grow faster, so take less time to reach marketable size • Benefits Farms produce more food, more quickly Farmers can use areas that are dry or saline to produce crops Farmers can use less pesticide • Knowledge needed for effective use Lifecycles, physiology & genetic techniques

5. Gene or seed banks Gene/seed banks involve storage of tissue samples or seeds to preserve genetic diversity. Examples include seed storage, cuttings from plants, frozen embryos, stem cells and tissue cultures or cell lines Principles for selecting the organisms for saving include health of organism & freedom from genetic disease, genetic diversity, degree of threat, ease of storage Problems include deterioration of stored samples, finding sufficient gene donors

6. DNA profiling DNA profiling involves identifying DNA sequences in individuals (DNA fingerprint) and species (genome) Special enzymes called restriction enzymes are use to split the DNA into segments so the sequence of nucleotides can be identified. It is used to • identify the genetic relationships between individuals (eg to ensure diversity when mating endangered species) • look for genetic disease (eg when choosing breeding stock, or seeds or tissue for storage) • establish phylogenic relationships (eg when classifying new species)

7. DNA Many new conservation techniques are using techniques based on genetic identification or manipulation. Genetic strategies rely on an understanding of DNA. The nucleus of a cell contains DNA (deoxyribonucleic acid) DNA is also present in mitochondria and chloroplasts (plants) DNA is arranged in structures called chromosomes, which are only visible when the cell is dividing. The genes carry all the information for the development of the organism. Genes provide information about making proteins. DNA is important as it controls cell activities and the appearance of individuals

8. How DNA works 1 Each gene is a section of DNA or sequence of bases. The base sequences on the DNA acts as a code that controls the action of the cell.

9. Structure of DNA DNA is a coiled double helix made up of nucleotides on a sugar phosphate backbone

10. DNA is made of nucleotides

11. Base pairing Adenine always pairs with Thymine Thymine always pairs with Adenine Cytosine always pairs with Guanine Guanine always pairs with Cytosine

12. How DNA works 2 The code sequences are copied as mRNA, which is sent to the ribosomes, and used as the instructions to make proteins. Amino acids are carried into the ribosomes by tRNA, which contain a 3 nucleotide section (anticodon) that matches with a 3 nucleotide section (codon) on the mRNA. Each base links up with its base pair - cytosine with guanine, adenine with thymine. This controls the order in which different amino acids are attached.

13. DNA codes for RNA RNA is also made of nucleotides and is very similar to DNA except: Thymine is replaced by Uracil The sugar in the sugar-phosphate backbone is different (ribose) Strands are single not double There are 3 types – mRNA, tRNA and rRNA

14. RNA structure Transfer RNA Messenger RNA Ribosomal RNA

15. DNA controls protein synthesis

16. Definitions 1 • DNA – deoxyribonucleic acid – carries the code that controls RNA production. This is a double helix • m-RNA - has the set of instructions for the order in which amino acids are to be assembled into proteins. This is a single strand of nucleotides • t-RNA - carries amino acids to the ribosome. This is a single strand of nucleotides

17. Definitions 2 • Protein - long chains of amino acids, usually folded • Amino acid - building blocks of proteins • Ribosomes – site of protein synthesis – where mRNA is read. These are made of rRNA • Endoplasmic reticulum – membrane channels that ribosomes are attached to. Is responsible for transport and remodelling of protein (eg refolding or attaching carbohydrate groups to make glycoproteins)

18. Definitions 3 • Transcription - copying of DNA to make RNA. Uses the base pair rule Cytosine in DNA  Guanine in RNA Guanine in DNA  Cytosine in RNA Adenine in DNA  Uracil in RNA Thymine in DNA  Adenine in RNA (RNA contains Uracil not Thymine) • Translation - reading of mRNA to make proteins

19. Definitions 4 • Codon - 3 base segment of mRNA – codes for particular amino acid • Anticodon - 3 base segment of tRNA (carrying a particular amino acid) that is the reverse of the codon on mRNA • Triplet – 3 base segment of DNA – that is the reverse for mRNA – which codes for a codon • Gene – section of DNA that controls one characteristic or protein • Start codon – the codon (AUG) that tells the ribosome to start making a protein

20. Definitions 5 • Coding strand – the strand of DNA that has the same sequence as he RNA (but is not used to make the RNA) • Template strand – the strand of DNA that is the complement of the coding strand (the side that is used to make the RNA) • RNA polymerase – enzyme that makes the new strand of RNA

21. Definitions 6 • Introns – nonsense sections in mRNA that are removed before it leaves the nucleus • Exons – the sections that code for protein sequence. When the mRNA leaves the nucleus it will have only exons

22. Why are proteins important? Roles of proteins in the body include • Structural proteins eg collagen, keratin • Enzymes (organic catalysts) eg digestive enzymes • Transport proteins eg haemoglobin • Regulatory proteins eg hormones • Protective proteins eg antibodies, clotting factors

23. Gene expression Each cell contains many genes that carry the information for making many proteins. But not all of these genes are expressed in all cells in the body eg skin cells produce pigment (melanin) but do not make contractile proteins like muscle cells

24. Gene expression Gene expression is controlled by a number of factors. • Regulator genes produce proteins that bind to an operator gene and inhibit transcription • Operator genes is the start of a structural gene • Promoter genes indicate the structural genes that should be used to make particular mRNA at any given time • Environmental factors may turn genes on or off (epigenetics) by affecting how the DNA is coiled around the histones (and so whether it can be read easily)

25. DNA replication DNA is capable of replication to produce identical copies This occurs in interphase – before mitosis starts One set of enzymes split the strands Another set of enzymes join new nucleotides to each strand Nucleotides match up by the base pairing rule (C – G, A - T) The end result is two identical strands, joined at a point called the centromere

26. DNA replication 2

27. Comparing mitosis and meiosis

28. Comparing mitosis and meiosis