Or each chromosome of a pair can be individually picked. 16. Explain two ways in which children can have different chromosomes (gene variation) than their mother or father. Random separation of chromosomes (law of segregation) when forming sperm/ova during anaphase I, crossing over of some genes to the homologous chromosomes during prophase I, and mutation during S
Studying Inheritance of Mutant Alleles in Drosophila By: Christopher R. Dangaran Lab# 9 Lab Partner: Cody De La Mater Biology 171L (FRI) November 18, 2011 TA: Kelly Williams Introduction: Flies in the family of Drosophila serve as excellent candidates for genetic studies due to their ability to reproduce quickly and low chromosome count (lab manual). One of the most commonly used flies in these genetic studies are Drosophila melanogaster, commonly, albeit incorrectly, known as fruit flies due to their affinity for fungi that grow on rotting fruits. They are also sexually dimorphic, making distinguishing between the genders more easily. Males are typically smaller than females, and have rounded tails whereas the females have rounded abdomens. The banding patterns on the abdomen also differ between males and females; males have a more uniform color while females have more distinct banded pattern (lab manual).
The crossing in the F2 generation of the heterozygous male and heterozygous female produced two heterozygous offspring, one homozygous recessive offspring and one homozygous dominant offspring. Discussion This experiment was conducted by using aldehyde oxidase (AO) to genetically characterize the aldox gene. It was hypothesized that the gene
A recessive allele will only be expressed if the genotype is homozygous. Heterozygous genotypes containing one dominant trait and one recessive trait will only express the dominant trait in the phenotype. If we do a pure breeding (monohybrid cross) between two parents, where one parent contains dominant homozygous alleles for black eyes and another parent contains recessive homozygous alleles for brown eyes, we will find all black eyes among the offspring of F1 generation. We can demonstrate this by using a punnet square. B B Bb | Bb | Bb | Bb | b b All (Bb) heterozygous genotypes are expressing the phenotype of black eyes.
Explain. 3 points. Theoretically, yes. All cells are derived from the zygote. However, there can be somatic mutations that could change the DNA in random cells.
Why is this different? Normal body cells have a complete set of chromosomes. If normal body cells from mom and dad fused to form a baby, the fertilized egg would have twice as many chromosomes as it should. Meiosis is sometimes called "reduction division" because it reduces the number of chromosomes to half the normal number so that when fusion of sperm and egg occurs, baby will have the correct number. Therefore the purpose of meiosis is to produce gametes; the sperm and eggs.
The long, thin ascus causes both meiotic spindles and the mitotic spindles to be aligned during spore formation. As a result, the positioning of the ascospores directly reflects the arrangement of homologous chromosome pairs during metaphase I of meiosis (Glase, 1995). This allows us to detect which alleles were exchanged creating crossovers. Sexual reproduction in the S. fimicola is important because an it allows for a significant source of genetic variability, and allows the fungus to adapt to new environments (Fincham, 1971). This genetic variability is obtained when crossovers occur between
Sperm will travel through the cervix and into the fallopian tube. If conception takes place, the sperm penetrates an egg and creates a single set of 46 chromosomes called a zygote, which is the basis for a new human being. The fertilized egg spends a couple days traveling through the fallopian tube toward the uterus, dividing into cells ; it is called a morula. The morula becomes a blastocyst and will eventually end up in the uterus. Anywhere from day 6-12 after conception, the blastocyst will imbed into the uterine lining and begin the embryonic stage.
The type of Down syndrome depends on how many cells have the extra or abnormal chromosomes. Medical experts believe the cell changes most often start in a woman's egg before or at conception. Less often, the error occurs in sperm at conception. It is not known what causes the cells to divide abnormally. One type of Down syndrome, called translocation-type, may be passed down through families which are inherited”.
When Gender Matters: Sex Linked, Sex Limited and Sex Influenced Traits For most inherited traits, the gender of the bearer of the genes is immaterial. Characteristics like free earlobes, fur color, etc., generally operate the same in males as they do in females. But there are exceptions. These fall into three primary categories. Sex Linked Traits are traits whose loci are literally on the sex chromosomes, so their transmission from generation to generation is affected by the sex chromosome complement of the individual.