150 likes | 272 Views
Do now:. How would you or the person that bred Dachshunds create them? Meaning what are the steps – they are “designer dogs” Answer – take a small breed of dog and breed with another small breed and then continually take the smallest of the litter and breed them.
E N D
Do now: • How would you or the person that bred Dachshunds create them? Meaning what are the steps – they are “designer dogs” • Answer – take a small breed of dog and breed with another small breed and then continually take the smallest of the litter and breed them. • They were designed to chase foxes during fox hunts. They purposely breed small dogs, each surviving litter only the smallest were breed with other small dogs of another litter of the same breed. • One of the earliest “Selective breeding”
Homework due today was • For next class: read pages 392 – 397, Human Chromosomes (chapter14, section1) • Define these terms: • Karyotype • Genome • Sex Chromosomes • Autosomes • Pedigree • Co-dominant (again) • Sex linked gene
Homework due tomorrow • For next class: read pages 398 – 401 • Summarize the reading in your notebooks. • Also, the research project. See the handout. • Fraternal versus Paternal Twins – Landt • Tri Chromosome 21 (Downs Syndrome) – Guerin • Placental previa –Frisoli • Placental abruption - Dubinsky • Cerebral Palsy – Briggs • Conjoined Twins – Litman • Turner Syndrome – Shaw-Vicente • Edwards Syndrome (Trisomy 18) - Pesner • Patau Syndrome (Trisomy 13) – Nihan • Cystic fibrosis - O’Connor • Osteogenesisimperfecta – Filingeri
How can selective breeding help with reconstructing dinosaurs? • They can match an elephant (Asian Elephant) with a woolly Mammoth, each time re-matching to eventually get a very close (but not exact) match. • Essentially, they are cloning the Woolly Mammoth. • What will the issue be once it is complete? • Lack of genetic diversity
DNA material - review • Genome - full set of information that an organism carries within its DNA • Karyotype – Shows a complete diploid (2 sets of chromosomes) grouped together in pairs. • Pg. 392 – male or female? • This karyotype? Male or • Female?
Chromosomes • The sperm from the male carries 23 chromosomes and the egg from the mother carries 23 chromosomes. Each half is known as a “haploid”. The 2 haploids (23 chromosomes + 23 chromosomes ) will equal 1 diploid (46 chromosomes).
Haploid vs. Diploid • Females have 2 copies of X chromosomes (meaning XX determines female) and males have 1 copy of Y chromosomes (meaning XY determines male). • Haploid – half the set of chromosomes – meaning what each parent gives to the child • Diploid – the full set of DNA
Who is responsible for the babies sex? • All eggs carry X chromosomes, but 50% of the sperm carry X chromosomes and 50% carry Y chromosomes. So the male is the determining factor. • Why did Henry the VIII have so many wives? • All his wives were to blame for not granting him a son, but it was actually him. • For the record, Henry had six wives. It was Henry’s fault.
Sex Chromosomes vs. Autosomes • Autosomal chromosomes – the first 22 sets (44 genes) of chromosomes are known as Autosomal chromosomes or autosomes. • We do not count the 2 sex chromosomes.
New Material • Most follow the principle of dominance – meaning if a dominant allele appears then the dominant trait will express itself. • Hair color – BB, Bb or bb • (P. 394) Blood type for example, known as Rhesus. Rh+ & Rh- (Rh+ is the dominant) so an individual with Rh+ & Rh- will be Rh+ same as hair color. • Slightly different – Co-dominance & Multiple alleles such as in the ABO Blood group • This is determined by from 3 different alleles IaIb and i. Alleles Ia & Ib are both co-dominant, i is recessive. (look at chart on page 394. Please re-read codominant & multiple alleles.
New material • Sex-linked inherence: • Colorblindness for example. Carried on the X chromosome. For a female to carry the recessive gene she would have to have it on both the X chromosome. Since males only have one X chromosome it cannot be cancelled out with the other sex chromosome gene since it is Y. • This is why it is far more likely to find a male with color-blindness than a female.
Our experiment? • Write what we are trying to do with the seeds?
Inbreeding • Continuous breeding of an individual with similar characteristics. • What is the danger? • Too close to one another genetically so both the good genes and the bad can remain, and be expressed. Much like the Amish where after a few generations there is very little variation.
Biotechnology • Purposely adding in variation (mutation) to improve the breed. • Our seed experiment is an example of Biotechnology. We are adding in a seed that was modified to stop weeds from growing.