CHAPTER 11CHROMOSOME “ISSUES”

Genetic Disorders:

Recessive (t)- Caused by

receiving 2 “bad” recessive alleles

- Ex. T= normal t = albino

tt = albino disorder

Dominant (T)- Caused by

receiving at least 1 “bad” dominant allele

- Ex. T = dwarf t = normal

Tt = dwarf disorder

Pedigree

Is a diagram that Traces the

inheritanceOf a particular trait Through several Generations.

Sex-linked Traits pg 307

Occur on the X chromosome at number 23.

More frequent in males

Ex. Colorblindness

11.2 Complex Patterns of inheritance

Incomplete Dominance

= the heterozygous genotype creates a new phenotype!

Codominance

= both alleles are dominant and therefore a combined phenotype is shown

Incomplete dominance pg. 302 R = red flowers r = white flowers

RR – red rr - white

Rr = pink

Codominance pg. 302

Both alleles show dominance!

Ex – blood types Type AB shows the

A allele as well as the B allele!

Polygenic Traits pg. 309

Traits such as height, skin color, that are determined by several Genes, not just two alleles!

karyotype

Picture of all of your 46 chromosomes - paired!

Law of segregation pg. 279

= “states that two alleles for each trait separate during meiosis.

Upon fertilization (zygote) they will reunite!

Law of Independent Assortmentpage 280 “states that alleles

randomly distribute themselves during meiosis.

Genes on separate chromosomes will switch.

This allows for more variation!