Bio quiz Genetics

Question 1

Determine blood type by petigree/genotype?

Answer 1

IA and IB are codominant alleles
i is recessive
IAIA or IAi = Type A blood
IBIB or IBi = Type B blood
IAIB = Type AB blood (universal acceptor)
ii = Type O blood (universal donor)

Question 2

Know what a cross test is?

Answer 2

Mate the “unknown” organism with a homozygous recessive organism!
-If all offspring show dominant phenotype, “unknown” was homozygous dominant
-If half of the offspring show the dominant phenotype and half show the recessive phenotype, “unknown” was heterozygous

Question 3

Keryotype/keryogram?

Question 4

Figure out the possiblities of a certain trait in offspring?

Answer 4

Genotype: An organism’s genetic information.

Phenotype: A set of observable traits.

Question 5

Be familiar with mendle?

Answer 5

Gregor Mendel (1865, Austrian Monk) – the “Father of Genetics”
Began studying genetics by performing experiments with pea plants and following their traits for several generations (P generation = parent, F1 generation = first offspring generation, F2 = second generation offspring and so forth;
Example: Your parents are P, you are F1, and your children would be F2
Used true-breeding pea plants and cross pollinated them (mixed gametes) to follow specific traits – typically picking different alleles for traits to cross (seed color, seed shape, height, flower color etc.).
Note: “true-breeding” = homozygous
Collected LOTS of data/ statistically analyzed

Question 6

Know what polygenetic inhertance is?

Answer 6

-Two or more genes affecting the expression of a single trait
-Most human traits are believed to be polygenic because they show too many phenotypes to be -produced by just one gene
-Polygenic inheritance produces continuous variation: lots of possible phenotypes
-As the number of genes influencing the trait increases, so do the possible # of phenotypes
-If a trait can be easily categorized to a few distinct phenotypes, it does not demonstrate continuous variation (Blood type)
-When there are many possible phenotypes (and many intermediate possibilities), the trait demonstrates continuous variation and produces a bell shaped distribution curve

Question 7

Be able to identify reconbaints by %.

Answer 7

To determine if genes are linked: complete a punnett square for the cross (to see the expected geno/ phenotypes) and compare it to the actual phenotypes of the offspring
Are they as expected or significantly different?
If significantly different, are MOST of the phenotypes observed the SAME as the parents’ phenotypes? If so, genes are LINKED (loci are on the same chromosome)

Question 8

Linleage group definition and notion?

Answer 8

Linked genes are found on the SAME chromosome, so they are inherited TOGETHER (as a linkage group)
Notion?

Question 9

Definition of codominance?

Answer 9

Some genes have two (or more) dominant alleles = codominance (equally powerful, so if inherit both dominant alleles, both are expressed in the phenotype)