Module 27 Terms - Mendelian Genetics

Question 1

Dominant

Answer 1

The phenotype that is expressed over the other when two purebred organisms are crossed

Question 2

Recessive

Answer 2

The phenotype that is not expressed when two purebred organisms are crossed

Question 3

Alleles

Answer 3

Genes (specific locations on a chromosome) that have different versions of a DNA sequence

Question 4

Monohybrid cross

Answer 4

A cross between individuals that are hybrids for a single gene, meaning they possess two different alleles

Question 5

Law of segregation

Answer 5

Only one of the two gene copies present in an organism is distributed to each gamete (egg or sperm cell) that it makes, and the allocation of the gene copies is random

Question 6

Homozygous

Answer 6

Possessing two copies of the same allele for a given trait (ex: AA)

Question 7

Heterozygous

Answer 7

Possessing two nonidentical alleles for a given trait (ex: Aa)

Question 8

Addition rule of probability

Answer 8

The probability of two mutually exclusive (independent) events happening is the sum of their individual probabilities

P(A or B) = P(A) + P(B)

Question 9

Multiplication rule of probability

Answer 9

The probability of two independent events both happening is the product of their individual probabilities

P(A and B) = P(A) * P(B)

Question 10

Chi-square (χ^2) test

Answer 10

χ^2 = (o - e)^2
………..Σ———
………………e

o = observed value
e = expected value

The Σ sign means you should add the calculations for the phenotypes in question.

Helps determine whether a difference between the number of expected and observed counts is large enough to be considered statistically significant enough to reject the null hypothesis or not

To find the degrees of freedom, subtract the number of observed categories by 1 (a category could be green and yellow pea pods, for example)

Question 11

Law of independent assortment

Answer 11

The alleles of two (or more) different genes get sorted into gametes independently of one another. In other words, the allele a gamete receives for one gene does not influence the allele received for another gene.

Regardless of the parental phenotype, the offspring inherit different combinations of the traits from the parental genotype

Question 12

Dihybrid cross

Answer 12

A cross where all individuals are hybrids for two traits coded by different genes. Organisms produced by this cross come in a 9:3:3:1 ratio

Question 13

Pedigree

Answer 13

A visual map of phenotypes that uses ancestral relationships