What is the genotype of this reebops? N= L= S = E = A = B = T = H = Could one of its parents have had 3 humps? Is it possible for both its parents to have had blue legs? Could both of its parents have had no antenna? (H)

Learning objectives today….. What is an allele & what are dominant and recessive alleles? Can we predict phenotype from genotype? What is a “genetic diagram”? What is polydactyly and how is it inherited? What is CF and how is it inherited?

What are dominant and recessive alleles? ………………… allele controls traits/ features that only show when there is no dominant allele in your genotype ……………….. allele takes over control of a feature whenever it is in your genotype T = dominant (curly) t = recessive (straight) What do these reebops alleles code for? A a B b L l H h

AlleleCodes forDominant or recessive? A a B b L L H h

Ann Ken FifiSal Jack What is Ken’s genotype? What is Jack & Sal’s genotype? Who has Jack inherited his genotype from? What is Ann’s genotype? You have enough information to be certain What is Fifi’s genotype (you have enough information to be certain) Ann is pregnant. What is the chance that her next child will be a boy? Jack meets Jade. What is the chance they will have a curly tailed child? Jade

What is Ken’s genotype? What is Jack & Sal’s genotype? Who has Jack inherited his genotype from? What is Ann’s genotype? You have enough information to be certain What is Fifi’s genotype (you have enough information to be certain) Ann is pregnant. What is the chance that her next child will be a boy? Jack meets Jade. What is the chance they will have a curly tailed child?

How can we predict what traits our kids might get? Mum’s genotype Dad’s genotype Possible genotypes of kids

Some genes have more than one version Different versions of a gene are called “alleles” Remember… Genotype Phenotype

Some genes have more than one version Different versions of a gene are called “alleles” Remember… Genotype Phenotype

x ?? ? Predict the chances of the couple having a)A blue eyed child b)A brown eyed child

x ?? ? What is Hannah’s phenotype? (1 mark) What is the chance of Pete having blue eyes? (3 marks) What is the chance of Pete having Brown eyes? (3 marks) How could Pete have blue eyes when neither of his parents do? (2 marks) ? John Hannah Pete

Heterozygous = 2 different alleles eg Bb Homozygous = 2 same alleles eg bb or BB

Polydactyly Condition caused by a dominant allele

Mum’s genotype dd Dad’s genotype D d

Cystic Fibrosis A disease of the cell membrane Caused by a recessive allele Can 2 “healthy” parents have a kid with CF?

How is genetic information copied into new cells? What is mitosis and what’s it used for? What’s so special about meiosis? What is embryo screening and is it right? What are stem cells and is it right to use them? Passing the DNA onto new cells

1.Mitosis Used for …………… old or damaged cells or to ……….. bigger (increase the number of cells) No voice over but the animations in this video clearly show how and why cells divide by mitosis. How is genetic information copied into new cells?

Most cells have 2 copies of each chromosome 1.Genetic information copied 2.Cell splits into 2 genetically identical cells 1.Mitosis

Most cells have 2 copies of each chromosome 1.Genetic information copied 2.Cell splits into 2 genetically identical cells 1.Mitosis

Zygote grows as cells divide by Mitosis In the early growth stages the embryo cells are unspecialised stem cells

How is genetic information copied into new cells? Gametes have single chromosomes so only carry one of the parents alleles 2. Meiosis

Chromosome pair in Dad’s testes Gametes are made in MEIOSIS This only occurs in the ovaries or testes Why do gametes only have single chromosomes? Sperm (gamete) made from this cell

Chromosome pair in Dad’s testes Why do gametes only have single chromosomes? Sperm (gamete) made from this cell If the parent has 2 different alleles (heterozygous) meiosis will result in 50% of the sperm getting one allele and 50% getting the other

Chromosome pair in Dad’s testes Why do gametes only have single chromosomes? Sperm (gamete) made from this cell If the parent has 2 identical alleles (homozygous) meiosis will result in 100% of the sperm getting that allele.

Actually meiosis makes four gametes from each body cell, because the genetic information is copied, and then the cell divides twice to form four gametes. Why do gametes only have single chromosomes? Higher only!

Zygote grows as cells divide by Mitosis In the early growth stages the embryo cells are unspecialised stem cells

Screening for genetic disorders This clip helps summarise the techniques used to screen for genetic disorders Some words to help you! Fertilised egg / zygote Blastomeres DNA Genetic disorders.

What are the advantages and disadvantages (social, economic and ethical) of embryo screening? AdvantagesDisadvantages Economic Social Ethical Jan 10 BLY2H Q5

Evaluate NO marks for just telling them what they told you Why is the thing good? (2 points) Why is the thing bad? (2 points) Your own opinion, with acknowledgement that there are 2 sides to the argument eg “I think screening is right as the benefits of eradicating illnesses outweigh the moral problems of destroying embryos”….

Can stem cells really cure disease? What is a stem cell? Where do stem cells come from? What are stem cells used for? Is it right to use stem cells in research and medical treatments?

What is a stem cell? An “unprogrammed” cell that can develop into ……………….. other type of cell. In the “right” conditions this cell could become a muscle cell In other conditions this cell could instead become a bone cell

-cell-research-and-medicine/6013.html LZ Clip discussing use of stem cells and ethics surrounding their use Where do stem cells come from? What are stem cells used for? The best source of stem cells is ………………………………………………………… Human stem cells can also be found in adult’s ………………….. ………….. Stem cells can be programmed to develop (differentiate) into …………….type of cell. Stem cells could be programmed to become nerve cells and used to treat …………………………………… Anthony Atala