Animal Genetics Exam 1

• Genetics

• Statistics

Animal Breeding

• Discipline in animal science that utiizes the principles of _____ and _____ with the goal of improvement of animals.

• Science that helps in the quest to breed better animals

  • Started with domestication → successful to change animals in . desired ways.

Art

Robert Bakewell

• 1700s

• Father of the ____ of Animal Breeding (at the time it wasn’t a “science)

  • Had definite ideas about breeding livestock

  • Responsible for BREEDS → developed grouping animals based on characteristics and desired traits

    • Shire horses, Leicester sheep, Longhorn cattle

Progeny Testing

Robert Bakewell

• Never sold males, he leased them → beginning of _______

inbreeding

Robert Bakewell

• Mated the best with the best, regardless of their relationship

• Used _______ for increased homozygosity

Genetics

Gregor Mendel

• 1860s

• Father of ______

• established the basic genetic principles

  • used PEA PLANTS

• not well understood during his life

Population Genetics

Sewell Wright & Ronald Fischer

• 1920s

• Pioneers of _____

Genetic Drift

Sewell Wright & Ronald Fischer

• researched the effects of inbreeding and crossbreeding

• known for the concept of ______

statistical

Sewell Wright & Ronald Fischer

• provided _____ basis of inheritance

Science

Jay Lush

• 1930s

• Founder of the ____ of Animal Breeding

  • Separated sperm into X and Y sperm → allows for gendered semen

  • Dairy cattle breeder

Breeding Values

Jay Lush

• Created _____- to refect the genetic make-up of an animal

Predict

We want to understand the genetic principles of inheriticane to _____ potential outcomes

• progeny phenotyoic distribution

• changes in a population

• next record, genetic merit, response to selection

Start of Lecture 2

Start of Lecture 2

Blending

_____ Theory

• Theory of inheritance prevailing at the time of Mendel’s work

• Hereditary material consisted of fluids that became permanetly mized when combined.

• This theory was directly contradicted by Mendel and other’s work

Pure Breeding Strain

_______: A strain in which animals of like phenotypes perpetuate those phenotypes in their progeny

• Ex: dalmation: same phenotype displayed in each generation

F1

EX: Newfoundland Breed

Black (Purebred) x Bronze (Purebred) → Black (everbody)

• The resulting progeny is known as ____ (first fillial generation)/hybrid

Hybrid

_______: a progeny resulting from the mating of different pure breeding strains

• usually referred to as F1 animals

Backcross

Mating of F1 Animals

____: mating of F1 animals back to an animal of one or the other of the pure breeding strains used to create the F1 animals

• F1 x Black/Bronze (Purebred)

Interse

Mating of F1 Animals

______: mating among themselves

• F1 x F1

• results in first unusual result

Bronze

Inter Se

• When mating F1 x F1, the parents both have black phenotypes, however there is a reappearance of ____ progeny in backcross an interse mating of F1 animals

• Mendel created a hypothesis to explain these results

Particulate Theory

What was the name of the hypothesis Mendel created to explain the reamergence of Bronze phenotype?

Factors

Particulate Theory: genetic material consists of distinct _____ that maintain their intergrity over generations

• He didn’t know what the factors were, now we know that they are genes

pairs

Law of Segregation: Factors appear in ____ and a random member of the pair is passed from parent to progeny

• Pairs

• Segregation

• Random

2

Law of Segregation

• Pairs: factors/gene come in pairs of ___.

Parent

Law of Segregation

• Segregation: each memeber of pair in offspring comes from each ____.

Random

Law of Segregation

• ____: copy we recieve from each parent is random

Dominant

• One factor is capable of masking the presence of the second factor in the expression of a phenotype. This factor is said to be ____

  • This is only observed when the two alleles are together

Recessive

The factor being masked is said to be ______

Chromosomes

________- long strands of DNA in the nucleus of cells

Locus

_________- specific place on a chromosome occupied by a gene

Gene

______- the basic unit of inheritance. A sequence of DNA that codes for proteins

Allele

_____- an alternative form of a gene

Genotype

_______- Genetic composition of an individual → depends of alleles

• Aa, AA, aa

Phenotype

_____ or trait - Physical expression of a genotype (what we see)

Alleles

Example: Coat Color → Trait

• 2 ______: B = Black; b = bronze

• Possible Genotypes: BB, Bb, bb

• Possible Phenotypes; Black or Bronze

>

Matings

B & b

• B = allele for black

• b = allele for bronze

Practice Question Format

B = Black

b = bronze

B __ b → shows which allele is dominant.

Underscore

Matings

Practice Question Format

BB = Bb = B_ = BLACK (the ______- shows that it doesn’t matter which allele an individual gets it will always be black)

bb = BRONZE

Hetereozygote

Genotypes (__ __ (pair of alleles))

• _________: an individual prossessing two different alleles at a locus

Homozygote

Genotypes (__ __ (pair of alleles))

• _________: an indivudal possessing two of the same alleles at a locus

  • **Must specifiy whether it is recessive or dominant

hybrid

Crossing Pure Breeding Strains

BB x bb → Bb (this is F1 or ___)

Gametes

Segregation - Single Locus

• A parent has Bb genotype, the possible ____ are B or b, the frequency of each of those being passed onto progeny is .5 and .5 → no priviledge/preference

Recombination

______: combining possible gametes to give a new set of alleles

**Review Punnet Square, Genotypic Ratio and Phenotypic Ratio

Test Cross

______: A cross involving one parent showing the dominant phenotype and one parent completely recessive

• dominant phenotype x recessive phenotype

  • Test to determine the second allele in an individual showing the dominant phenotype (carrying one dominant allele) → determines dominant phenotype

Bb

Test Cross

• If dominant parent is BB = all progeny will be ___ (black) → no bronze

Bb

Test Cross

• If dominant parent is ____ = progeny wil be ½ Bb + ½ bb (1/2 black and ½ bronze)

Independent

Law of _____ Assortment

• Describes inheritance of multiple traits

• Loci influencing different characteristics segregate at random with respect to each other

  • Each pair of factors separates independently

dihybrid

Combination of Traits

• Following the inheritance of more than on trait at a time

• For two loci the F1 is referred to as a _____ (heterozygous at two loci)

  • BbAa

Independently

Ex: Landseer Breed

• Coat Color: black/bronze

• Ticking - the presence of flecks of color in the white area

  • Segregate _____

Start of Lecture 3

Start of Lecture 3

Pairs

Chromosomes appear in _____

• Full complement of chromosomes = 2n, where n is the number of chromosomes in a set

diploid

Organisms having 2n chromosomes are referred to as _____

haploid

Organisms having n chromosomes are referred to as _______

Gametes

____ are the reproductive cells often called sex cells

Sperm

The male gamete is ____

• Haploid

Egg

The female gamete is an ____

• Haploid

Haploid

Gametes (sperm/egg) have 1 set of chromosomes (n), referred to as _____.

• Only cell in body that has just one copy of chromosomes

zygotes

The fusion of male and female gametes form ____ - which are again diploid (2n)

Meiosis

Reproductive cycle

• ____ is the process that produces gametes (n)

random

Genetic Inheritance is composed of two ____ processes

1. Formation of Gametes

2. Formation of Zygote

Random

Genetic Inheritance

1. Formation of gametes - ____ reduction from dipolid to haploid

Union

Genetic Inheritance

2. Formation of zygote - random ___ of gametes (restoration of diploid cell)

Probabilistic

The two random processes that make up genetic inheritance results in matings that are ____ (can predict)

likelihood

Probability - Mathematical _____ (chance) that a particular event will occur.

• Denoted as: P(event)

  • EX: P(blue eyes)

• NEVER

• ALWAYS

Properties of Probability

1. Probability of an event is a number between 0 and 1 (0 < P < 1) → don’t use percentages

• P=0 means event ___ happens

• P=1 means it ____ happens

1

Properties of Probability

2. The total probability of all possible events always sum to ___

Number of total observations

Calculating Probabilties

• P(event) = # of observations of the event / _________

Ex: tobiano spotting → spotted horse where typically white appears across the black and all four legs

Review

Calculating Probabilities Example

NOT

Independent Events - probability that one event occurs is _____ influenced by the occurence of a second event

AND

Joint Probability - probability of two or more events occuring together

• Can be recognized by the word “____” (multiplication of probabilities)

• and that the traits can occur in any combination

In punnet square separate all of the traits and find their probabilities seprarately

Extension

Joint Probability Example (1)

• The basic components of color in horses are black and chesnut

  • E = Black, e = chesnut | E>e

    • E is the color used to designate the ____ locus

  • T = spotting, t = solid | T>t

dihybrids

Joint Probability Example (2)

From mating ____ (both traits are heterozygous), what is the probability of a progeny with black coat color AND spotting?

Review

Joint Probability Example (3)

• Focus on each separate set of alleles! not the particular event where they both happen to occur!

Dogs

Inheritance of Spotting in Cats

• S = spotted, s = solid | S>s (Reverse in ____ (Solid is dominant))

precludes

Mutually Exclusive Events - The occurence of one event _____ the occurence of a second event

• Example: spots - if spotted can’t be sloid

• One event occurs and prevents the other event from happening → events cannot occur together

OR

Mutually Exclusive Events

• The probability of mutually exclusive events is represnted by the word “____” (addition +)

Sum

P(A or B)

• Rule: The probability of two or more mutually exclusive events is the ___ of the probability of each event

GIVEN

Conditional Probabilities

• Probability of an event A _____ a second event has occured

  • Event happened, whats the probability that another event occurs

• The P(A and B) is a singular probability (one where both occured → not the same as joint probability)

Review

Conditonal Probabilities Example

• The P(SS and spots) is the probability of one indiviudal in the punnet square

OUT OF

Probabilities of Distributions of Events

• Example: What is the probability that in 4 progeny observed from mating heterozygous Tobiano spotted horses we observe 3 being spotted and one being solid?

  • "_______”

4

Probability of Outcomes

• Determine the probabilities of events occuring in a punnet square

  • Observe ___ Progeny

Total

Probability of Outcomes

• T = # of horses with spotting (that we are looking for)

• S = # of horses that are solid color (that we are looking for)

• T + S = N = ___ # of horses

  • Solve everything in the brackets first then multiply together

1

Factorials - Denoted by !

• Multiply by N-1 stopping at 1

• Rule: 0! = ___ (will need to know this rule)