Human Genome Project

Go to Human Genome Project Information Archive and explore the chromosomes.

Assessment criteria Unit 3

1. Define the following terms: genotype, phenotype, dominant, recessive, homozygous, heterozygous, gene, hereditary disease.
2. Explain and predict probabilities of outcomes from genetic crossing involving one or two genes (dihybrid crossing) and:
   1. Two homozygous parents.
   2. Two heterozygous parents.
   3. One homozygous and one heterozygous parent.
   4. Sex-linked characteristics.
   5. Linked genes.
   6. Codominance.
   7. Intermediate inheritance.
3. Explain a sex determination cross.
4. Understand how to interpret family pedigrees and to find out the genotypes of the members of the family.
5. Know some examples of inherited conditions: haemophilia and colour-blindness.
6. State Mendel’s laws (name and conclusions) and explain Mendel's experiments
   1. First law and first experiment : Crossing of two pure-breeding plants for one trait (tall/short).
   2. Second law and second experiment: Crossing of two plants from the F1 of the first crossing.
   3. Third law:
      1. Third experiment: Crossing of two pure-breeding plants for two traits (tall/short and purple/white).
      2. Fourth experiment: Crossing of two plants from the F1 of the third crossing.
7. Explain the exceptions to Mendel’s laws: intermediate inheritance, co-dominance, gene linkage and genetic recombination.
8. Know what a mutation is and the different types of mutations according to:
   1. The size: gene,chromosomal, genomic (aneuploidy and euploidy)
   2. The type of cell.
   3. The effect, giving an example of a beneficial mutation.
9. Give an example of a genetic disorder caused by a genomic mutation.
10. Give an example of a genetic disorder caused by a gene mutation.
11. Explain what amniocentesis is.
12. Explain what a molecular test is.
13. Explain what a carcinogen is and name one example of each type of carcinogen.

Mutations

Read this text and make a diagram to classify mutations according to the resulting protein.

DNA extraction

Questions

1. What type of cells have you used in this experiment?
2. Have you been able to observe that the DNA sample that you have obtained has formed long, white threads? Are you able to come to any conclusion about this?
3. The detergent provokes the breakage of the cells. What other macromolecules is it necessary that the liquid dish soap denaturalizes so that the DNA uncoils?
4. Do you believe that the sample that you have gotten is pure or is it mixed with some other molecule?

Homework

Activity 1

Recall the text Bad luck, read this paragraph and write a conclusion including these words: controversy, scientists, environmental factors, bad luck (random mutations), cancer, probability.

El entorno condiciona la respuesta a la enfermedad más que la herencia

Hace no mucho, la ciencia parecía dar la razón a quienes creían en el destino, aunque este no estuviese escrito en las estrellas sino en el interior de nuestras células. La secuenciación de genomas completos ayudaría a predecir qué enfermedades podría padecer una persona cuando se aproximase a la vejez y qué hábitos debería evitar para sortear los riesgos escritos en sus genes.

Sin embargo, aunque la herencia tiene una influencia importante en muchas enfermedades, estudios recientes muestran que la predicción de nuestro futuro va a requerir más que leer y entender el código genético.

Recientemente, un polémico estudio publicado en la revista Science, afirmaba que la 'mala suerte' explica dos tercios de todo el riesgo de cáncer en un tejido mientras que las variables genéticas y ambientales explican otro tercio. Ahora, un trabajo publicado en Cell concluye que las variaciones en el sistema inmune, el departamento de defensa del organismo que ayuda a combatir el cáncer y el resto de enfermedades, le deben mucho más a las experiencias y al entorno en que se ha vivido que a las condiciones heredadas. Para responder con éxito ante una infección o un tumor incipiente, el mecanismo de protección del organismo debe ser flexible frente a las presiones ambientales y la experiencia vital de cada individuo lo personaliza.

If you want to read more

 

Extra. Units 2 or 3. Mysterious genome.

Did you know that your cells contain several thousand copies of an organelle that maintains its own genome? 

And that instead of being linear, like the chromosomes found in the nucleus, the genome of this organelle is circular?

Go

Genetic problems

In cats, fluffy is dominant to silky and chubby is dominant to skinny.

1. One parent is homozygous silky and homozygous chubby. The other parent is heterozygous for all traits. What percentage of the offspring may be fluffy and thin?

2. One parent is homozygous fluffy and heterozygous chubby and the other is homozygous silky and heterozygous chubby.
   1. What percent of their offspring could be fluffy and chubby?
   2. What percent of the offspring could be homozygous for fluffiness?
   3. What percent of the offspring could be homozygous for chubbiness?
3. Both parents are heterozygous for both traits
   1. What fraction of the offspring could have the exact same genotype as the parents?
   2. What fraction of the offspring could have the same phenotype as the parents?

In eagles, bald is dominant to feathers and loner is dominant to groupie.

4. One parent is heterozygous bald and homozygous loner. The other is homozygous recessive for both traits.
   1. What percentage of the offspring may be feathered loners?
5. One parent is homozygous dominant for both traits and the other is homozygous recessive for both traits.
   1. What percentage of the offspring may be bald groupies?
   2. What percentage of the offspring may be heterozygous for both traits?
6. One parent is homozygous bald and homozygous groupie. The other is heterozygous for both traits.
   1. What percentage of the offspring may be homozygous bald and heterozygous loners?
   2. What percentage of the offspring may be feathered groupies?

An aquatic arthropod called a Cyclops has antennae that are either smooth or barbed. The allele for barbs is dominant. In the same organism, resistance to pesticides is a recessive trait.

 

7. Make a "key" to show all the possible genotypes (and phenotypes) of this organism.

Unit 3.

Answer the questions and write a summary. You can visit this website to better understand how the MC1R gene works.

How Does Eye Color Work?

What makes eyes brown, blue, green, and so on?

Watch this video and answer the above questions.

Homework

GENETIC TRAITS?

1. Go over each of the following traits and determine if you or your relatives exhibit the phenotype. Also view the presentation that shows pictures of these traits at Human Genetic Traits

You can add more traits or diseases.

Trait Description	Yourself	Your relatives
Ear points (Darwin's Point)
Tongue rolling
Plays a sport
Attached earlobe
Plays an instrument
Hitchhiker’s Thumb
Upturned Nose
Left-Handed
Freckles
Bent little fingers
Curly hair
Short big toe
Eye Color (blue?)*
Straight Hairline (not widow's peak)
Chin dimple or cleft
Hand clasping, left over right thumb
Hair on middle joints of fingers
G.P.A. (grade point average)of 4 or above (A students= 10 students)
Ring finger longer than index finger**
Likes broccoli
Arm folding ­ fold arms across stomach, is left on top?
Popularity (how many consider themselves popular)
Nearsighted
Gap between front teeth

2. Make a pedigree of your family showing the treats you share with your relatives (you can use colors to represent each treat). (Note: circles:women).