Chromosomal and histological evidences of infertility in F2 and F2 backcross. Hybrid generations of Clarias anguillaris and Heterobranchus longifilis

Male meiosis was studied in 9 different mating combinations in parental, first, second and backcross generation hybrids of Clarias anguillaris and Heterobranchus longifilis. 27 bivalents were recorded in metaphase I for seven mating combinations. The number of bivalents in F1 hybrid male x C. anguillaris female could not be determined due to a high degree of clumping of the chromosomes. All metaphase I cells observed in female F1 hybrid x male H. longifilis had three complex bivalents consisting of 43.3% giant ring and 56.7% giant rod chromosomes. The number of ring bivalents per cell was higher in parental H. longifilis than parental C. anguillaris. The number of ring bivalents per cell increased from F1 (6.7 and 8.2) to F2 backcross (13.5) hybrid generations indicating increasing chromosomal instability of backcross hybrids over Fl and F2 hybrid

Techniques of producing monosex or sterile population of fish for aquaculture -- a review of selected literature

The need to develop techniques that can make the male grow faster in many species of fish as well as the female in some other species cannot be over-emphasized. Monosex culture of the faster growing sex can increase production if the method is reliable. The use of such techniques as manual sexing, sterilisation, hybridization, gynogenesis, androgenesis polyploidy and sex-reversal can provide solutions or partial solutions to the problems associated with sexual difference, sexual maturation and unwanted reproductio

Wanted More from Moore

I was very excited when I first picked up Wes Moore’s book The Other Wes Moore. After hearing that it was chosen as the common reading text for the incoming class, and also being given the opportunity to co-facilitate a discussion based on the book, I was even more excited. However, as I read the book, I found myself more frustrated than fulfilled. [excerpt

Boys Will Be Boys, Girls Will Be...

Lets talk about sex. Well not really, just the double standard that comes with the topic. It’s no secret that men and women are taught to think about sex differently. While there are many (myself included) who fail to accept these culturally imposed ideas and attitudes about sex, it would be incredibly naïve to not acknowledge the existence of the double standard that exists. [excerpt

That Awkward Moment When I Accidentally Internalized Racism

I recently attended a conference about the importance of Africana Studies (AFS) and it had a panel of visiting professors that consisted of mostly black men and women. I was beyond impressed by their achievements and found myself engaged and excited by their discussions. My admiration for these scholars only grew exponentially when I learned that one of the female professors was from Sierra Leone, just like me! [excerpt

To Empathize With An Enemy

I do not like to talk about my time in Sierra Leone, but I think I’m ready to start. Growing up in Sierra Leone was probably the best thing that ever happened to me. I carry with me fond memories of my childhood, growing up on 22 Thompson Street in the one-storey house with red doors and windows and zebra themed paint. Evenings were spent riding bikes with my best friend Fatmata. Weekend afternoons spent playing scrabble and watching our favorite Disney movies with my siblings and neighbors in our living room. Those memories I have kept, happily. [excerpt

Studying Abroad, Toilet Paper, and Other Exercises in Missing the Point

I have been in Ghana only for a few days, and I can already tell I am going to love the place­—the people, the food, the environment, all remind me of my home country, Sierra Leone. However, I don’t think I can adjust to the constant uttering by some of my peers about how this experience “makes them appreciate how much they have.” In the past four days, I have heard that same phrase over and over again. [excerpt

Selma is America

During my recent trip to Selma, Alabama, I was overwhelmed by the tangible evidence that blatant racism and segregation still exists. In a town where many had made great sacrifices to combat America’s racial injustices, it was disheartening to see how very little change had come to the town MLK described as the “most segregated” in America. [excerpt

Style Watch: Blackface Edition

The above quote is from a statement/apology offered by Sebastian Kim, a photographer, whose recent editorial, “African Queen,” which featured a 16-year-old white female made to appear black, was marred with controversy. According to the photographer, dousing a young white female in deep bronze, accessorizing her in elaborate head wraps and heavy jewels (symbols that are often associated with Africa), was in no way an attempt to depict what an “African queen” looks like. Rather, his spread was attempting to showcase “the beauty aesthetic of his shoot” by using a “tanned or golden skin” model. [excerpt