Sex Ratio - Science topic

When to breed buffaloes to produce more female calves? ज्यादा कटड़ी पैदा करने के लिए भैंसों में प्रजनन कब कराएं? https://azad-azadindia.blogspot.com/2023/12/when-to-breed-buffaloes-to-produce-more.html

After breeding your buffalo, you wait about 10 months (305-320 days) to see whether your buffalo calved a male or female calf. However, data analysis revealed that you may enhance the chances of having more female calves by timing the breeding of your buffaloes. After analyzing buffalo birth data retrieved from Annual reports of ICAR-Central Institute for Research on Buffalo (CIRB), Hissar (2019-2022, four years), it was interesting to note that the probability of birth of female Murrah buffalo calves was twice (Odds Ratio >2; CI95, 1.02-2.290) than the birth of male calves in July and August. This means you should breed your Murrah buffalo in October and November to have more female calves. At Nabha, Punjab Centre of CIRB Nili-Ravi buffalo breeding is done. The birth data of Nili-Ravi buffalo also indicated two months with much higher possibility of birth of female calves (Odds ratio 4.5 in April, CI99, 1.02-19.5; Odds ratio 2.3 in September, CI99, 1.04-5.08) than male calves, that means you should breed Nili-Ravi buffalo either in July (for calving in April) or in December (for calving in September). This analysis is based on four-year data only (2019 to 2022), in the period a total of 632 Murrah calves and 532 Nili-Ravi calves were borne. The bigger data analysis may yield better statistics and may guide the buffalo farmers to breed the buffaloes profitably. The data needs to be handled carefully as if the climate of the month of breeding may affect the sex ratio then certainly, the best months of breeding may be different in different regions of the country. Therefore, calving data at different breeding centers needs to be relooked for the benefit of livestock farmers.

Especially in favor of females in this case.

In reviewing research on Australian species (Hyriidae), I’ve encountered many examples where sex ratios are clearly biased towards males or females. These often are large samples, numbering in the hundreds, and most of the biases are statistically significant. I know that age and population density are implicated in research on species of Margaritiferidae and Unionidae, and that there may be differential mortality associated with dissolved oxygen levels (in that situation, brooding females are more vulnerable to hypoxia than males). The incidence of hermaphrodites may also need to be factored in.

In our Australian examples, the biases for any one species may differ between different times or places. There is little possibility of biased sampling, as these species are not sexually dimorphic.

Is anyone aware of published studies that shed more light on these seemingly haphazard shifts in favour of one sex or the other?  

Hello!

A question. Does anyone happen to know of any studies on the influence of surrounding land use (natural habitat, mass-flowering crops, other agriculture, etc.) on the sex ratio of the offspring produced by solitary bees (possibly specifically mason bees but not necessarily)?

To date, I have only found studies that indicate that larger individuals produce more females and that the proportion of females decreases through the season.

Thanks in advance!

I would like to determine live sex ratio of sperm cells in ejaculated semen samples. I wonder whether staining with Hoechst 33342 and propidium iodide and flow cytometric analysis has enough accuracy and resolution to differentiate and quantity the live X- and Y-bearing spermatozoa. Does it need to be done by a cell sorter machine or could be done by a regular flow cytometer which is able to read both stains?

Thank you in advance.

I am using genomic DNA from sperm as the template, try to do sex-ratio relative quantification, when I ran the qPCR, it shows the shoulder in the melt curve, When I ran a gel for the qPCR products, it shows one band, but above the bands, there are some none specific thing shown up.

I am using a autosomal primer for reference gene, but either using autosomal primer or GAPDH, it gives me the shoulder in the melt curve.

1) the primers are optimized for this PCR 2) there is no primer dimers.

Can this be a problem when running the gDNA as template? Or using ROX and SYBR will give the problem?

Is this a good way to do the sex-ratio determination? When I did the calibration curve, more input of my template, did not increase the CT value (improve the CT value).

I want to employ Occupancy and Detection probabilitiy estimates for a large vertebrate species. Do you recommend using and running different models with presence-absence matrices by sex (i have robust data on the sex ratio in my study population), or using sex as a covariate (i.e. using the typical species presence-absence matrix) of occupancy/ detection? The rest of the covariates will be from the habitat type and the species community at my study sites.

Thanks.

According to the 2011 census of India the socio-economic, political and educationally developed districts of Odisha are found huge differences of sex ratio.

India's sex ratio (about 1070 males per 1,000 females) is much higher than the global sex ratio (about 1012 males per 1,000 females). What may be its possible reasons? In India, only in Kerala, with large Christian population, females are more than males (about 923 males per 1,000 females). What may be the reason of this exceptional ratio?

I am currently planning to work on the Study of breeding biology of Glossogobius guris (Freshwater Goby) in particular reservoir (Rajdhala Beel, NetraKona) in Bangladesh for my MS thesis. I am interested to know how this study of breeding biology of Freshwater Goby in this reservoir can have socio-economic contribution. I will determine the GSI, Fecundity and Gonadal Histology, sex ratios, etc. of the particular population from the samples . Some past studies demonstrated that this species has good abundance in the reservoir. But no one worked on the breeding biology of this species in this area. How I can explain the socio-economic contributions of this study? I have already made some points of myself but additionally I need some strong points from the experts to make the objectives of the study more acceptable and more convenient in terms of benefit of people and the fisheries sector. Thanks in advanced for any kind of response anyone might provide.

In general, sex ratio is expressed as the ratio of males to females in a population, ie number of males/number of females (*100). However, when the number of females in (sub)population is 0 (zero), how to express the sex ratio?

Why sex ratio studies in wild natural population are limited?

We are working on gene expression in chicken shell gland and would like to assess how much of expression may occurred in the erythrocyte and non-erythrocyte. Therefore, a rough proportion would provide us a clue. Answers are very much appreciated.

guard family, bitter gourd, monoecious, gynoecious line, sex forms and sex ratio

Since 4 years, our association studies the demography of a European pond turtle population (Emys orbicularis), located on a wet area (about 7 ha) in southeastern France. This population is totally isolated. There is no road nearby, not limiting (apparent) factors that may cause high adult mortality. Laying areas are located near water areas in relatively well preserved terrestrial habitats. However, a significant reduction of the water surface is observed.

We found a growing imbalance in sex ratio, a very low survival and a large decline in the number of breeding males over time.

Do you know of a similar case?

I did a statistical analysis by spss the chi -square test for the sex ratio I found values X2 = 856,717a Is it normal?

I'm working on a database of patients (all diagnosed for cancer)  included in a clinical trial.  I'm trying to perform a comparison between those patients and patients not included in clinical trials to be treated.

In general population you can easily calculate the sex ratio of patient in the dataset by using incidence tables (to take into account age and sex repartition in general population).

But for a clinical trial, i don't know how i can perform a such thing.

i have conducted an experiment aimed at investigating the effect of aloe on sex ratio in tilapia. I found out that aloe at low inclusion level presented a significant difference compared to the control, the following inclusion levels did not present any significant difference when compared to aloe unsupplemented fish, however, significant different was again present at the highest dosage. How do i explain this pattern of data in this field. literatures are also welcome.

It is proved that stopping rule behaviour does not have an effect on sex ratio at birth but it is still believed that it has effect on sex ratio at last birth. How to correct the sex ratio at last birth? What are the policy options? Just focusing on sex selective abortions through legal means may not help the developing countries like India? What are alternative options? Will correcting sex ratio of last birth contribute to balance the sex ratio? The last birth comprising 20% to 30% of total births in a country with TFR of 2.6, so there is a need to encourage the parents that even they can stop the family size with a female child. What kind of incentives need to be announced for them? India is already offering conditional cash transfer but not exactly to the girl child who is last birth of the parents. Is it acceptable if the government offers incentives for parents who have a female child as last birth with parents having only two children?

In other words, it is possible that the sex ratio of one given insect varies from year to year with light trapping?

There are many references about bias in sex ratio in chicken , but no one performed direct selection on the trait , I designed my study to do selection on dam for this traits , but I need references about previous studies to avoid any replicate mistakes 

What are the implications of biased sex ratios in hummingbirds? Do we have 1:1 sex ratio? Is that the norm? Or does it vary with the intensity of sexual dimorphism? Any good references on this question?

Dear Colleagues

What is the sex ratio in carabids?

As you all know pitfall trapping gives a bias estimate of abundance due to various reasons. Therefore higher abundance of males or females in the trap does not have to relate to their abundance. Do you know sex ratio of ground beetle populations obtained with more reliable methods than Barbet traps? Do you have some unpublished data on this topic?

With kind regards

Taking several confounding factors, such as residence, SES, mothers age, populations, inbreeding etc how can we get an adjusted value and risk analysis (odds ratio). Which software is best for such analysis?

The reproductive features are: Fertility, mortality, sex ratio, selection intensity. For each of the reproductive feature please suggest an appropriate statistical model. 

What are the list of statistical tests we can do for Sex Ratio, to know whether the sex ratio is significant or not in Tribal and in Non tribal

Under what circumstances does a female skewed sex-ratio in a population become desirable or detrimental to the local population of a species?

A fundamental question to evolution theory is: why is sex so common? Specifically, in multicellular animals it is common to have equal sex ratios of females and males. Imagine in such a population a female that asexually produces only female offspring that again produce only female offspring: compared to the rest of the population they would have a doubled fitness (cf. Red-Queen-Hypothesis).

Thus one would ask: why is sex so common? But is it? Humans have about 10^14 cells, which requires at least 46 mitotic cell cycles to grow. Thus, when considering a multicellular animal as a colony of cells, sexual reproduction is still quite rare, in our case only once in at least 46 generations! I wouldn't call that often.

How many rats do I need to determine the sex ratio? How many animals should I use to ensure that the result is statistically significant?