Simple Inheritance 1. Brown Hair is dominant. What are the odds of a heterozygous and homozygous recessive individual having a child that is also heterozygous for brown hair? 50% chance Bb If a couple have 20 kids and they are all heterozygous for brown hair, use a Punnett square to show the most likely genotypes of the parents. For all kids to be heterozygous the parents are very likely BB x bb One parent is UU and the other is Uu for unibrow, which is dominant. What are the phenotypic ratios for this cross? 100% Unibrows! B b Bb bb B b Bb U UU u Uu

Co-Dominance A certain species of moth is orange, black, or both orange and black. An orange moth and a black-orange moth produce 500 offspring. How many of each possible phenotype can you expect? 50% Black and Orange 50% Orange So… 250 Black and Orange and 250 Orange 5. A brindle dog is black and tan. If two brindle dogs mate, what would the phenotypic offspring be? 50% brindle (BT), 25% black (BB), & 25% tan (TT) O B BO OO B T BB BT TT

Incomplete Inheritance A certain species of gerbil comes in three varieties – black, gray, and white. A black and a gray gerbil mate and produce 10 offspring. How many gray gerbils will they most likely produce? Out of 10… 5 (50%) would be Black (BB) and 5 (50%) would be grey (BW) David has curly hair (CC) and Susie has wavy hair (SC). What are the phenotypic ratios of their offspring? 50% will have curly hair and 50% will be wavy hair B BB W BW C CC S CS

X-Linked 8. Color blindness is an x-linked recessive disorder and normal color vision is dominant. Mom is color blind and dad sees normal color. What are the odds their daughters will be color blind? What about their sons? I used ‘N’ for normal vision since it is dominant, which means ‘nn’ is recessive and COLOR-BLIND! Of the girls, none of them (0%) will be color-blind because they each have a dominant ‘N’ allele. Of the boys, all will be color-blind because they don’t have the dominant allele for normal vision! 9. XBXO and XOY are two cat parents expecting kittens. Coat color exhibits co-dominant inheritance. What are the phenotypic ratios of their offspring? Xn XN XNXn Y XnY X Y

Blood Typing A CSI team is investigating a crime scene. Video shows four people entering and exiting during the hour of the crime. Allen, Bubba, Charlie, and Debbie were seen and have mysteriously all left town. The CSI team tracked down their parents. The parent genotypes of the parents were as follows: Allen – AB and OO, Bubba – AB and AO, Charlie – BO and AA, and Debbie – OO and BB. If type O blood is found at the crime scene, which suspects can be ruled out? These are the PARENTS of each suspect. That means that whatever is in the boxes are the possible phenotypes of the children (Allen, Bubba, Charlie, and Debbie). Type O(only type O genotype is OO) was found at the scene which means if the suspect didn’t have type OO, they can be eliminated as a suspect. The blood at the scene could NOT have been any of the suspect because none of them have type O! So you can rule them ALL out! David’s wife is type A blood and David is type B blood. What are ALL of the potential phenotypes of the their offspring? Al A B O AO BO AB Bub A B AA AB O AO BO Ch B O A AB AO Deb O B BO A B AB A O B AB BO A B AB O AO A O B AB BO AO OO Their kids can have ALL phenotypes (A, B, AB, or O) because all of those are represented in the possible boxes to the left!

KNOW THESE DEFINITIONS!! A. Homozygous B. Punnett square C. agglutinate D. Heterozygous E. allele F. gene G. TT H. Tt I. tt J. Dominant K. recessive L. co-dominant M. Incomplete dominance N. loci O. antigen Antibody Q. rh R. Monohybrid S. Genotype T. Phenotype Match the descriptions below to the proper terms from the word bank. If this allele is present, it WILL show up in the phenotype. A general reference to something on a chromosome that is inheritable. Meaning “one of each” allele A tool used to help determine a cross’s genotypes. To clump up or group together Meaning only one type of allele A code (or segment) on a chromosome that calls for a specific representation of a trait A genotype that means homozygous recessive A genotype that means heterozygous A genotype that means homozygous dominant Often referred to as a “hidden” trait or one that does not show up in the presence of an allele that is dominant Something in your body that tries to get rid of the bad stuff A specific location on a chromosome where an allele can be found Anything that is not supposed to be in your body (or something recognized as bad) An inheritance type where both phenotypes can be present on the same individual A term that describes the appearance of traits in an individual An inheritance type where a new, blended phenotypes shows up in an individual The protein found in some blood Crosses dealing with just one trait The combination of alleles (or all of the allele combination that an individual has) Dominant Gene Heterozygous Punnett square Agglutinate Homozygous Allele tt Tt TT Recessive Antibody Loci (this will not be on the test) Antigen Co-dominant Phenotype Incomplete Rh (this will not be on the test) Monohybrid Genotype

Dihybrid Crosses!! A dihybrid cross is when we want to take a look at two genes that are so closely linked on the chromosome that they are often inherited together. Problem: If Ewe is heterozygous for both Ugly and Stupid, which are both dominant traits, and Ewe marries Buck who is also heterozygous for both traits (and therefore Ugly and Stupid as well), what is the chance that their child will be good-looking AND smart? Both parents are this genotype: UuSs, so your cross will be UuSs x UuSs Good-looking AND Smart would be NOT Ugly AND NOT Stupid. That would be uu AND ss together. Find and count all of the ‘uuss’ in the chart above. There is only ONE. That means there is a 1/16 chance for their child to be good-looking AND smart! 1/16 = .0625 or 6.25% chance. US Us uS us UUSS UUSs UuSS UuSs UUss Uuss uuSS uuSs uuss