In this lab, you learn about the purpose of a karyotype and understand how it can be used to detect a chromosomal mutation. Let’s begin….

Checking for Anatomical Defect Checking for Genetic Material Defect  Ultrasound – Video of Ultrasound  Karyotype – Video on Understanding Karyotyping

Obtaining the Chromosomes for the Karyotype Blood culture 1 Centrifuge Packed red And white blood cells Fluid 2 Hypotonic solution 3 Fixative White Blood cells Stain 4 5 Centromere Sister chromatids Pair of homologous chromosomes

1. You will simulate the karyotyping task 2. You will create a karyotype and determine the gender and developmental status of the baby. 3. You must carefully cut out all chromosomes and correctly match them up by the following criteria: a. Size - length b. Centromere location c. Banding pattern

An alteration in the total normal number of chromosomes An alteration in the structure of the chromosome  Humans normally have 46 chromosomes  45 means missing one  47 means has extra The karyotype below shows an alteration in number. Count…  Structure means length and banding pattern Two Categories: 1.Number Alteration 2.Structure Alternation

 A change in the way the chromosome looks…  *alleles duplicate  *alleles lost  *alleles switched positions  *alleles from one homologous pair on another pair Structural mutations are not good because genes (alleles) must occupy a specific location on a specific chromosome Look at the above pair. The colored dots are allele pairs. They must always be in the order shown.

Fiure 8.23A, B Deletion Duplication Inversion Homologous chromosomes translocation Nonhomologous chromosomes Structural Chromosomal Mutations

This means the organism has the wrong chromosome number Karyotype identifies structural and number mutation types. Look at the next slide of a Photograph of a karyotype. Can you find the mutations and identify type.

 Involves meiosis – cell division that makes gametes  Meiosis goes wrong!  The egg cell, sperm cell, or both have the wrong number of chromosomes

Examine the arrows. Pair 8 & 11 are trisomy and there is a 15, 17 translocation. Child has Both a structural and number mutation.

Each group must submit..  A Neat, 100% perfect karyotype  A completed lab sheet (Ques #1-5 done) For Homework Define the following in your notebook. a. Translocation b. Inversion c. Duplication d. Deletion e. Trisomy f. Monosomy 2. Which terms represent an alteration in number mutation? terms e and f 3. Which terms represent an alteration in structure? terms a, b, c, d

The Cause for an egg or sperm cell to have the wrong number of chromosomes It is the failure of chromosome pairs to separate during meiosis, gamete formation. When Olivia makes her egg, the pairs must separate. Click on next Slide to see her pairs separate.

Olivia Pre-egg Cell with only two Pairs showing… So there are 4 chromosomes in the Sister chromatid form. The eggs produced will have 2. Final chromosome # is 2 for each cell. Good eggs! Final chromosome # is 2 and 1 for each gamete. Bad eggs!

Egg cell Sperm cell zygote Does the zygote (Junior) have the correct number of Chromosomes? No! Which gamete resulted from nondisjunction?

 Twizzler Nondisjunction Twizzler Nondisjunction  Animation of Nondisjunction Animation of Nondisjunction