Genetics

Zygote

Fertilized egg

Mitosis

Simple division of one cell into two, produces genetically identical daughter cell

Meiosis

Cell division into 4 haploid cells, produces gametes and genetic diveristy

Centromere

Where homologous chromosomes attach

23

How many pairs of chromosomes do humans have

Stages of Mitosis

Prophase

Metaphase

Anaphase

Telophase

Prophase

Phase where chromosomes begin to condense and centrioles are duplicated; where crossing over occurs in meiosis

Metaphase

Phase where chromosomes line up and prepare for dividing

Anapahse

Phase where chromosomes are pulled apart and cell begins to divide

Telophase

Phase where nucleus reforms and cells begin to be distinct

Phases of Meiosis

Prophase I

Metaphase I

Anaphase I

Telophase I

Metaphase II

Anaphase II

Telophase II

Metaphase II

Chromosomes line up for a second time and prepare to divide

Anaphase II

Chromosomes are pulled apart and a haploid cell begins to form

Telophase II

Cell begins to divide further nucleus is reformed; haploid cell is formed

gametogenesis

Production of sex cells

Gamete

haploid reproductive cell

Spermatogenesis

Production of sperm

Oogenesis

Production of eggs

In the primordial germ cells near the outer wall of the seminiferous tubules of the testicles

Where does meiosis occur in males

Near the surface of each ovary

Where does meiosis occur in females

Synapsis

The joining of two cells, typically gametes to form a zygote

4

Spermatogenesis produces (blank) equally sized sperm cells

Spermatid

A not fully mature sperm

Steps of Spermatogenesis

Primordial germ cells replicate and forms the primary spermatocyte

Primary spermatocyte divides to form 2 secondary spermatocyte

Secondary spermatocytes divide to form spermatids

Spermatids cytoplasm dissolves and forms tails to create sperm

Steps of Oogenesis

Primary germ cell replicates to form primary oocyte

Primary oocyte divides to form the first polar body and the secondary oocyte

First polar body divides to form 2 secondary polar bodies and the secondary oocyte divide to form a polar body and an ovum (egg)

They die and are reabsorbed

What happens to the polar bodies in Oogensis

3

How many polar bodies are formed in Oogenesis

Fertilization

Union of sperm and egg to from a zygote

Locus

Location of a gene on a chromosome

Homologous chromosome

Chromosomes that are paired in diploid cells

Cytosine-Guanine

Thymine-Adenine

What are the base pairs of DNA

Proteins

Genes code for (blank)

Steps of Protein synthesis

Transcription

Translation

Transcription

DNA is encoded into mRNA which leaves the nucleus for the next step

Translation

tRNA then enters the ribosome and protein synthesis begins

X and Y

What are the main sex chromosomes

Male

In mammals who determines the sex

Birds

Which species does the female determine the sex

Homozygous genes

Genes that correspond in a trait that they control EX. aa AA

Heterozygous genes

Genes that do not correspond on the traits they control Ex. Aa

Allele

Genes that occupy corresponding loci in homologous chromosomes but affect characteristics in differing ways

Identical allele

Genes that are alike and that affect the trait in the same way

Dominant Gene

Gene that overpowers the expression of another gene

Recessive Gene

Gene that is suppressed by another gene

Genotype

The genetic makeup of an organism

Phenotype

The physical appearance of an organism

Linear interaction

When a gene interacts with another gene in the same chromosome

Allelic interatction

When a gene interacts with its corresponding gene on a homologous chromosome

Epistatic interaction

When a gene interacts with another gene that is not on the same or homologous chromosome; alters or masks the expression of other genes

Linear

(blank) interactions are known to exist is lower animals but not livestock

Lack of dominance

When a heterozygous organism shows a mix of both homozygous organisms Ex. LL (long ears) vs ll (no ears) Ll(short ears)

Additive Gene Action

When each gene has an expressed phenotype

D= gene controlling rate of gain

D=.1

d=.05

DD increases gain by .2

Dd increases gain by .15

dd increases gain by .1

Overdominance

Heterozygous organisms are superior to either homozygous organisms (heterosis)

Partial Dominance

Heterozygote expresses phenotype intermediate to either homozygote byt most resembles homozygote dominate

True

Environment can affect phenotype (T/F)

False

Genotype has nothing to do with how well an animal will preform in its environment (T/F)

False

If environment plays a huge effect on production traits we can best improve that through genetic improvement (selective breeding) (T/F)

Standardize

Producers want to (blank) their environment

Superovulation

Producing a greater number of eggs than normal, usually utilized in order to impregnate multiple surrogates

Sexing of Semen

Determining the sex genes a sperm is carrying in order to determine the sex of the embryo that will result

Embryo splitting

Splitting an embryo in order to create clones

Embryo transfer

Transferring an embryo to a recipient animal to carry it to full term

Genetic scissors

Enzymes can act as (blank)

Somatotropin

Growth hormones often utilized in dairy cattle

Improves litter size and FE

Decreases time to market and carcass fat

Trangenic pigs

Pigs that have genes from other species to create more desirable traits

Nuclear fusion

Fusion of nuclei from two sex cells, artificial fertilization that can be transferred to surrogate

Gene therapy

Injection of genes into cells to treat/cure genetic diseases