Download Presentation

Genetics Since
Mendel
Page 2
Environmental Role
1. The environment plays a role in
how some of your genes are
expressed.
2. These influences may be internal
or external.
3. Example: Some people may be at
risk for skin cancer. These people
need to limit their exposure to the
Sun.
Polygenic Inheritance
1. Poly is a prefix meaning more than one.
2. Polygenic inheritance occurs when a
group of gene pairs act together to
produce a trait.
3. Eye color, height, hair color, and skin
color are examples of polygenic
inheritance.
Recessive Genetic Disorders
1. Both parents have a recessive
allele that is responsible for the
disorder and pass it on to the child.
2. Because the parents are
heterozygous, they don’t show
symptoms.
3. Treat this as dominant/recessive
when working Punnett square
problems.
Will the offspring be male or female?
1. Chromosomes/genes that determine the sex of an
organism are XX in females and XY in males.
2. Females produce eggs with an X chromosome
only.
3. Males produce sperm with either an X or a Y
chromosome.
4. Who determines the sex of the offspring?
Mutations
1. Mutations occur when a gene is altered or copied
incorrectly.
2. A mutation may be harmful, beneficial, or have no
effect.
3. Chromosome disorders are caused by more or fewer
chromosomes than normal.
4. These can occur because of mistakes during the
process of meiosis. (Which would pass this disorder to
the offspring.)
Pedigree
• A pedigree follows a trait through generations of a
family.
• https://www.youtube.com/watch?v=Wuk0W10EveU
Selective Breeding
1. Involves selecting qualities within individuals of a breed that are
desired so that these qualities may be passed on to the next
generation.
2. Inbreeding produces individuals with similar characteristics.
Selective Breeding
3. Hybridization involves crossing individuals
with different traits.
• This is done with the hope of producing offspring
with the best traits of both organisms.
What is genetic engineering?
1. Today scientists can use biology or chemistry to change the
arrangement of DNA that makes up a gene.
2. This is used today for many reasons. One of those reasons is to
produce larger volumes of medicine.
3. Cloning is a type of genetic engineering.
4. In cloning, the genetic information from a single cell of an organism
is used to produce another organism with the same genetic
information.
What other ways can genes be used?
1. Genes can be changed by scientist
to make plants more resistant to
disease.
2. Genes from one type of plant may
be inserted into another type of
plant to help fight crop diseases!