Beefalo is a cross between Bison (buffalo) and domestic or exotic cattle of any breed. The purpose of the species cross was to blend the outstanding qualities of the Bison with outstanding qualities of the bovine breeds of the world. The cross between the Bison and beef breeds combined the superior hardiness, foraging ability, calving ease, and meat quality of the Bison with the fertility, milking ability, and ease of handling from the bovine. 

Zorse Liger

Human Heredity 14-1 A Picture of chromosome arranged in rows is a karyotype Humans have 23 pairs (46) chromosomes Two of the 46 chromosomes are called sex chromosomes because they determine an individual’s sex Females have two copies of a large X chromosome. Males have one X and one small Y chromosome

Human Heredity 14-1 The remaining 44 chromosomes are known as autosomal chromosomes or autosomes. All human egg cells carry a single X chromosome (23, X). However, half of all sperm cells carry an X chromosome (23,X) and half carry a Y chromosome (23,Y). This ensures that just about half the zygotes will be 46XX and half will be 46XY

Is this a male or female’s karyotype?

Human Heredity 14-1 Human genes are inherited according to Mendel’s principles. However, in order to apply Mendelian genetics to humans, biologists must identify an inherited trait controlled by a single gene. First they must establish that the trait is actually inherited and not the result of environmental influences. Then, they have to study how the trait is passed from one generation to the next.

Human Heredity 14-1 A pedigree chart shows relationships within a family. If a trait is dominant, then all family members who lack the trait must have homozygous recessive (aa, bb, ff, etc.) alleles.

ww WW or Ww? White forelock trait = Dominant trait Female Male Horizontal line connecting a male and a female represents a marriage Vertical lines and a bracket connect parents to their children ww WW or Ww? A shaded circle or square indicates that a person expresses the trait A circle or square that is not shaded indicates that a person does not express the trait.

Human Heredity 14-1 Some traits, such as the shape of eyes or ears are actually polygenetic, controlled by many genes. Of course, many personal traits are also governed by environmental factors. The human genome – our complete set of genetic information- includes tens of thousands of genes.

Blood Type Some of the very first human genes to be identified were those that control blood type. The best known genes that determine human blood types are the ABO blood groups and Rh blood groups. The Rh blood group is determined by a single gene with two alleles- positive & negative. The positive (Rh+) allele is dominant, so persons who are Rh+/Rh+ or Rh+/Rh- are said to be Rh positive! Individuals with Rh-/Rh- alleles are Rh negative!

Blood Type There are 3 alleles for the ABO blood group gene: IA IB and i Alleles IA and IB are codominant. The alleles produce molecules known as antigens on the surface of red blood cells Individuals with alleles IA and IB produce both A and B antigens, making them blood type AB The i allele is recessive.

Blood Type Persons with IAIA or IAi produce only the A antigen, so they are blood type A. Those with IBIB or IBi produce only the B antigen, so they are blood type B Those persons who are homozygous for the i allele (ii) produce no antigen, and have blood type O

Human Disorders Some genetic disorders are caused by autosomal recessive alleles carried on chromosomes. Examples: albinism, cystic fibrosis, galactosemia, phenylketonuria, Tay-Sachs disease.

Human Disorders Other genetic disorders are caused by the dominant alleles, that are expressed even if a recessive allele is present. Examples: achondroplasia, Huntington’s disease, hypercholesterolemia Co-dominant alleles (2 dominant alleles) cause other disorders. Example Sickle Cell Anemia Go over all the disorders in your textbook.

Human Chromosomes 14-2 **Chromosomes 21 and 22 were the first human chromosomes whose sequences were determined. **Chromosome 22 contains as many as 545 different genes **Chromosome 21 has about 225 genes.

Genes located close together on the same chromosomes are linked, meaning they tend to be inherited together. Sex-linked genes are those with a special pattern of inheritance located on the X or Y chromosomes. More than 100 genes have been found on the X chromosome. (Only a few have been found on the Y) Colorblindness – three human genes associated with color-blindness are located on the X chromosome.

Sex cell inheritance patterns for male and female children

Sex Linked Males have just ONE X chromosome. All sex-linked alleles are expressed in males, EVEN if they are recessive. So, if a male receives a recessive allele on the X chromosomes, the trait WILL be expressed. For a female to show the sex-linked recessive trait (such as color-blindness), she MUST receive 2 copies of the recessive allele, one on each of her X chromosomes. Hemophilia is another example of a sex-linked disorder. (2 genes for blood clotting on X chromosome)

Male The "a" recessive allele will be expressed in his phenotype  Female The "a" recessive allele will not be expressed in her phenotype

CHROMOSOME DISORDERS!! **There is a common error in meiosis called nondisjunction this means that chromosomes do not separate properly. Abnormal number of chromosomes may end up in gametes. Sometimes individuals may have 3 copies of a chromosome (trisomy) Down Syndrome – 3 copies of chromosome 21 Edward’s syndrome – 3 copies of 18 (trisomy 18) Klinefelter Syndrome – XXXY XXXXY Turner Syndrome – Females with only one X

Molecular Genetics 14-3 **Certain disease-causing alleles have slightly different DNA sequences from their normal counterparts. There are tests that can spot these differences. Labeled DNA probes are specific DNA base sequences that detect the complementary base sequences found in the disease-causing alleles. There are tests that search for changes in restriction enzymes cutting sites. Tests detect differences between lengths of normal and abnormal DNA

DNA FINGERPRINTING!! **No individual is exactly like another, except identical twins. **DNA fingerprinting analyzes sections of DNA that have little or no known function but vary widely from one individual to another.

How it works: Small samples of DNA are cut with a restriction enzyme. Separated by size with gel electrophoresis Fragments containing high variable regions are detected with a DNA probe, revealing a series of DNA bands of various sizes If enough combinations of restriction enzymes are used, a pattern of bands is produced that is different from the pattern of anyone else in the world.

Human Genome Project: How was it done? video