Chapter 4 Part 2- Genetics Since Mendel Life Science

Question…  If you crossed Purebred Red four- o’clock plants with Purebred White four-o’clock plants, what would the offspring look like?

 Remember… they were Pink !?!?!

 Incomplete Dominance- when two homozygous parents combine, the offspring results in a mixed (or blended) phenotype  The evil Grey chicken!?!?!

 When neither allele for a trait is Dominant.  The phenotype produced is a blending between the two homozygous parents. –The combining of Purebred Red & Purebred White produced PINK plants.

 Although Mendel studied peas that were controlled by two alleles, many traits can be controlled by more than two alleles…

Multiple Alleles  A trait that is controlled by Having more than two alleles is controlled by Multiple Alleles.  Traits controlled by Multiple Alleles produce more than three phenotypes of that trait.

Example of Multiple Alleles…  Blood Types: A, B, AB, and O. –The O allele is recessive to both A and B

Other Worksheet…  Phenotype: Genotype:  A - AA or Ao Genotype  B – BB or Bo Genotype  AB – AB Genotype  O – oo Genotype

 A and B are _______________ alleles  o is _________________  “ A Blood” you need _____ and _____  _____ and _____  “B Blood” you need _____ and _____  _____ and _____  “AB Blood” you need _____ and _____  shows______________  “o Blood” you need _____ and _____  Because it’s ___________

Polygenic Inheritance  Polygenic Inheritance- when a group of gene pairs acts together to produce one trait. –Which creates more variety in phenotypes

 What would be an example?  Many traits such as…Eye Color, Hair Color, Skin tone, & Handspan are traits produced by a combination of genes.

Human Genes & Mutations  What are Mutations?!?!?

Mutations  Mutations - a permanent change in the DNA sequence  A mutation can be harmful, beneficial, or cause no effect.

Chromosome Disorder  Chromosome disorders- caused by more or fewer chromosomes than normal –Downs Syndrome- caused by an extra chromosome (trisomy) at Chromosome 21

Recessive Genetic Disorders  Recessive Genetic Disorders are disorders passed through the Recessive alleles.  Both parents contain the recessive allele (containing the disorder) that comes together in the offspring.

 When both parents are Heterozygous, they do not show any symptoms –(Called “carriers” for the trait.)  Example- Cystic Fibrosis is a homozygous recessive disorder.

Sex-Linked Disorders  An allele inherited on a sex chromosomes ( X or Y ) is called a sex-linked gene.  Inherited conditions are linked with the X and Y chromosomes.

 Example- Color Blindness and Hemophilia

 Pedigree- used to follow or trace traits through generations of a family.

Section 3 III. Advances in Genetics A. Genetic Engineering- experimentations that changes the arrangement of DNA that makes up a gene.

Types: 1. Recombinant DNA  Inserting a useful section of DNA into a bacteria  Example- Creating Insulin (Page 143)

2. Gene Therapy-  When a “normal allele” is placed into a virus, the virus then delivers the normal allele when it infects a specific cell. (Figure 13 Page 144)  May be used to control Cystic Fibrosis and other disorders.

3. Genetically Engineering Plants-  Plants are created by genetically inserting the desired genes of one plant into another plant you want to show those genes.  Also genetically engineered: ANIMALS  “Cloning”